26. Troubleshooting and Repairing Problems

A long time ago, somebody proved mathematically that it was impossible to make any reasonably complex software program problem-free. As the number of variables increases, as the interactions of subroutines and objects become more complex, and as the underlying logic of a program grows beyond the ability of a single person to grasp all at once, errors inevitably creep into the code. Given Windows 10’s status as possibly the most complex software ever created, the bad news is that there are certainly problems lurking in the weeds. However, the good news is that the overwhelming majority of these problems are extremely obscure and appear only under the rarest circumstances.

This doesn’t mean that you’re guaranteed a glitch-free computing experience—far from it. Third-party programs and devices cause the majority of computer woes, either because they have inherent problems themselves or because they don’t get along well with Windows 10. Using software, devices, and device drivers designed for Windows 10 can help tremendously, as can the maintenance program we outline in the rest of the chapters here in Part VI. But computer problems, like the proverbial death and taxes, are certainties in life, so you need to know how to troubleshoot and resolve the problems that will inevitably come your way. In this chapter, we help you do just that by showing you our favorite techniques for determining problem sources and by taking you through all of Windows 10’s recovery tools.

Unfortunately, most computer ills aren’t resolved so easily. For these more intractable problems, your first order of business is to hunt down the source of the glitch. This is, at best, a black art, but it can be done if you take a systematic approach. Over the years, we’ve found that the best approach is to ask a series of questions designed to gather the required information or to narrow down what might be the culprit. The next few sections take you through these questions.

To learn how to back up a Registry key, see “Backing Up the Registry,” p. 675.

You can control how Windows 10 handles system failures by following these steps:

1. In the taskbar’s Search box, type advanced system, and then click View Advanced System Settings to open the System Properties dialog box with the Advanced tab displayed.

2. In the Startup and Recovery group, click Settings. Figure 26.3 shows the Startup and Recovery dialog box that appears.

3. Configure how Windows 10 handles system failures using the following controls in the System Failure group:

Write an Event to the System Log—Leave this check box activated to have the system failure recorded in the system log. This enables you to view the event in the Event Viewer.

Automatically Restart—This is the option that, when activated, causes your system to reboot when a stop error occurs. Deactivate this check box if you want to avoid the reboot. This capability is useful if an error message appears briefly before Windows 10 reboots. By disabling the automatic restart, you give yourself time to read and write down the error message.

Write Debugging Information—This list determines what information Windows 10 saves to disk (in the folder specified in the Dump File text box below the list) when a system failure occurs. This information—it’s called a memory dump—contains data that can help a tech support employee determine the cause of the problem. You have the following choices:

None—No debugging information is written.

Small Memory Dump (256 KB)—This option writes the minimum amount of useful information that could be used to identify what caused the stop error. This 256KB file includes the stop error number and its description, the list of running device drivers, and the processor state.

Kernel Memory Dump—This option writes the contents of the kernel memory to the disk. (The kernel is the Windows 10 component that manages low-level functions for processor-related activities such as scheduling and dispatching threads, handling interrupts and exceptions, and synchronizing multiple processors.) This dump includes memory allocated to the kernel, the hardware abstraction layer, and the drivers and programs used by the kernel. Unallocated memory and memory allocated to user programs are not included in the dump. This information is the most useful for troubleshooting, so we recommend using this option.

Complete Memory Dump—This option writes the entire contents of RAM to the disk.

Automatic Memory Dump—This option is usually the default, and it means that Windows 10 decides which of the other options to use when writing the debugging info. This is the way to go if you’re not getting any debugging info written to the disk. Why would that happen? Windows 10 first writes the debugging information to the paging file—Pagefile.sys in the root folder of the %SystemDrive%. When you restart the computer, Windows 10 then transfers the information to the dump file. Therefore, you must have a large enough paging file to handle the memory dump. If not, you don’t see the debugging data. The Automatic Memory Dump option can determine in advance whether there is enough room in the paging file and, if not, it will default to a smaller dump.

Active Memory Dump—This option (which is new to Windows 10) means that Windows 10 writes to the disk only those portions of RAM that were in use when the crash occurred. This is a welcome addition to the debugging options because the active memory is most likely to have information on the crash.

Overwrite Any Existing File—When this option is activated, Windows 10 overwrites any existing dump file with the new dump information. If you deactivate this check box, Windows 10 creates a new dump file with each system failure. Note that this option is enabled only for the Kernel Memory Dump and the Complete Memory Dump (which by default write to the same file: %SystemRoot%Memory.dmp).

4. Click OK in all the open dialog boxes to put the new settings into effect.

Check the developer’s website to see whether an upgrade or patch is available.

Run the application’s Repair option (if it has one), which is often useful for fixing corrupted or missing files. To see whether a program has a Repair option, use the taskbar’s Search box to type uninstall, and then click Change or Remove a Program. In the Programs and Features window, click the problematic application and then look to see whether a Repair item appears in the taskbar (see Figure 26.4).

Reinstall the program.

You should also examine the program’s readme file (if it has one) to look for known problems and possible workarounds. It’s also a good idea to check for a Windows 10–compatible version of the program if the program was originally written for an earlier Windows version. Again, you can also try the program’s Repair option (if it has one), or you can reinstall the program.

Similarly, if you recently upgraded an existing program, try uninstalling the upgrade.

For information on using Device Manger for troubleshooting, see “Troubleshooting Device Problems,” p. 609.

Close all programs—You can often fix flaky behavior by shutting down all your open programs and starting them again. This fix is particularly useful for problems caused by low memory or low system resources.

Log off Windows 10—Logging off clears the RAM and thus gives you a slightly cleaner slate than merely closing all your programs.

Reboot the computer—If you’re having problems with some system files and devices, logging off won’t help because these objects remain loaded. By rebooting, you reload the entire operating system, which is often enough to solve many computer problems.

Turn off the computer and restart—You can often solve a hardware problem by shutting off your machine. Wait for 30 seconds to give all devices time to spin down, and then restart.

Check connections, power switches, and so on—Some of the most common (and some of the most embarrassing) causes of hardware problems are the simple physical things. Therefore, make sure that a device is turned on, check that cable connections are secure, and ensure that insertable devices are properly connected.

The Troubleshooting window (see Figure 26.5) is divided into several categories (Programs, Hardware and Sound, and so on), each of which offers a few links to general troubleshooting tasks. (If you see a message asking whether you want the most up-to-date troubleshooting content, be sure to click Yes.)

Figure 26.6 shows the troubleshooters available for the Programs category as we wrote this chapter.

Therefore, it is welcome news indeed that Windows 10 ships with a Windows Memory Diagnostics tool that works with Microsoft Online Crash Analysis to determine whether defective physical memory is the cause of program crashes. If so, Windows Memory Diagnostics lets you know about the problem and schedules a memory test for the next time you start your computer. If it detects actual problems, the system also marks the affected memory area as unusable to avoid future crashes.

Windows 10 also comes with a Memory Leak Diagnosis tool that’s part of the Diagnostic Policy Service. If a program is leaking memory (using up increasing amounts of memory over time), Memory Leak Diagnosis will locate the problem and take steps to fix it.

To run the Memory Leak Diagnostics tool, follow these steps:

1. Use the taskbar’s Search box to type memory, and then click Windows Memory Diagnostic in the search results. The Windows Memory Diagnostic window appears, as shown in Figure 26.7.

2. Click one of the following options:

Restart Now and Check for Problems—Click this option to force an immediate restart and schedule a memory test during startup. Be sure to save your work before clicking this option.

Check for Problems the Next Time I Start My Computer—Click this option to schedule a memory test to run the next time you boot.

After the test runs (it takes 10 to 15 minutes, depending on how much RAM is in your system), Windows 10 restarts and you see (for a short time) the Windows Memory Diagnostic icon in the taskbar’s notification area. This icon displays a notification that shows the results of the memory test.

Windows 10 offers a feature called Problem Reporting that’s designed to make solutions available to anyone who goes looking for them. Windows 10 keeps a list of problems your computer is having, so you can tell it to go online and see whether a solution is available. If a solution is waiting, Windows 10 will download it, install it, and fix your system.

Here are the steps to follow to check for solutions to problems:

1. Use the taskbar’s Search box to type maintenance, and then click Security and Maintenance in the results. The Security and Maintenance window appears.

2. Open the Maintenance section and click Check for Solutions. Windows 10 begins checking for solutions.

3. If you see a dialog box asking whether you want to send more information about your problems, you can click View Problem Details to see information about the problems. When you’re ready to move on, click Send Information.

4. If a solution exists for your computer, you see it listed in the Maintenance section of the Action Center window. Click the solution to install it.

By default, when a problem occurs, Windows 10 does two things:

It automatically checks for a solution to the problem.

It asks whether you want to send more information about the problem to Microsoft.

You can control this behavior by configuring a few settings:

1. In the Security and Maintenance window’s Maintenance section, under Check for Solutions to Problem Reports, click Settings. The Problem Reporting Settings window appears.

2. Click Change Report Settings for All Users. The Problem Reporting dialog box appears.

3. To configure problem reporting, click one of the following options:

Automatically Check for Solutions—Activate this option (it’s the default) to have Windows 10 automatically check online for an existing solution to a problem.

Automatically Check for Solutions and Send Additional Data, If Needed—Activate this option to have Windows 10 automatically check online for an existing solution to a problem and to automatically send extra information about the problem.

Each Time a Problem Occurs, Ask Me Before Checking for Solutions—Activate this option to have Windows 10 prompt you to check for solutions and to send additional information about the problem.

Never Check for Solutions—Activate this option if you don’t want to report problems at all.

Allow Each User to Choose Settings—Activate this option if your PC has multiple users and you prefer that each user to choose his or her own reporting options.

4. Click OK to put the new settings into effect.

What you’ve got on your hands is a rather expensive boat anchor, not to mention a hair-pullingly, teeth-gnashingly frustrating problem that you have to fix now. To help save some wear and tear on your hair and teeth, this chapter outlines a few common startup difficulties and their solutions.

Some boot problems mercifully fall into the Temporary Glitch category of startup woes. That is, it could be that your PC has just gone momentarily and temporarily haywire. To find out, shut down the computer and leave it turned off for at least 30 seconds to give everything time to spin down. Turn your PC back on and cross whatever parts of your body you think might help.

A setting in your computer’s BIOS options might be preventing a normal startup. For example, one of us once had a PC that wouldn’t boot no matter what we did. When we decided to check the BIOS, we found that the hard drive wasn’t listed as the boot device! When we configured the BIOS to boot from the hard drive, all was well. Restart your PC and then press whatever key or key combination your BIOS requires to access the settings (usually the Delete key or a function key such as F2). If you don’t see anything obvious (such as misconfigured boot options), try resetting all the options to the default state.

Every now and then a defective device will interfere with the boot process. To ensure that this isn’t the case, disconnect every device that can be disconnected, and then try booting your newly naked PC. If you get a successful launch, one of the devices was almost certainly the culprit. Attach the devices one by one and try rebooting each time until you find out which one is causing the boot failure. You could then reboot without the device, update the device driver (if an update is available), and try again. If that still doesn’t work, the device is probably defective and should be repaired or replaced.

If you get no power when you press your desktop PC’s On switch, it’s likely you have a defective power supply on your hands, one or more of the power supply connections have come loose, or your power cord is not plugged in to a power source or has come loose. Check all the connections and, if they’re fine, replace the power supply. If nothing happens when you try to turn on your notebook or tablet PC, you might be looking at a drained battery. Connect the machine to a power source and try again.

This list comes from the Registry, typically from the following keys:

Click here to view code image

HKEY_CURRENT_USERSOFTWAREMicrosoftWindowsCurrentVersionRun
HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun

To find out whether one of the programs is causing Windows 10 to misfire at startup, disable the startup programs one by one (or use the method shown in the “Troubleshooting by Halves” sidebar later in this chapter) to see whether that solves the problem. To disable a startup program, click it and then click Disable.

However, what if Windows 10 will start, but you encounter problems along the way? Or what if you want to try a few different configurations to see whether you can eliminate startup items or improve Windows 10’s overall performance? For these scenarios, don’t bother trying out different startup configurations by hand. Instead, take advantage of Windows 10’s System Configuration utility, which gives you a graphical front end that offers precise control over how Windows 10 starts.

Launch the System Configuration utility (in the Search box, type msconfig and press Enter) and display the General tab, which has three startup options:

Normal Startup—This option loads Windows 10 normally.

Diagnostic Startup—This option loads only those device drivers and system services that are necessary for Windows 10 to boot. This is equivalent to deactivating all the check boxes associated with the Selective Startup option, discussed next.

Selective Startup—When you activate this option (this is the default), the following check boxes become available (see Figure 26.9): Load System Services, Load Startup Items, and Use Original Boot Configuration. From the previous section, you already know how to disable startup items, so here our only concern is system services. The Load System Services category refers to the system services that Windows 10 loads at startup. The specific services loaded by Windows 10 are listed on the Services tab.

You use these check boxes to select which portions of the startup should be processed.

To control startup services, the System Configuration utility gives you two choices:

To prevent Windows 10 from loading nonessential services, activate Selective Startup in the General tab and then deactivate the Load System Services check box. Click OK.

To prevent Windows 10 from loading specific services, display the Services tab and then deactivate the check box beside the service or services you want to bypass at startup. Click OK.

1. In System Configuration, activate the Diagnostic Startup option and then reboot the computer. If the problem did not occur during the restart, you know the cause lies in the system services or the startup items.

2. In System Configuration, activate the Selective Startup option.

3. In System Configuration, activate Load System Services; in Task Manager, disable all the startup programs; reboot the computer.

4. In System Configuration, deactivate Load System Services; in Task Manager, enable all the startup programs; reboot the computer.

5. The problem will reoccur either during the step 3 reboot or the step 4 reboot. When this happens, you know that whatever category (services or programs) you enabled before rebooting is the source of the problem:

If the problem reoccurred after you activated the Load System Services check box, run System Configuration and select the Services tab.

If the problem reoccurred after you enabled the startup programs, run Task Manager and select the Startup tab.

6. If you’re in System Configuration, click Disable All to clear all the check boxes; if you’re in Task Manager, disable all the programs.

7. Activate one of the services or enable one of the programs and then reboot the computer.

8. Repeat step 7 for each of the other services or programs until the problem reoccurs. When this happens, you know that whatever item you activated or enabled just before rebooting is the source of the problem.

9. In the System Configuration utility’s General tab, activate the Normal Startup option.

10. Fix or work around the problem:

If the problem is a system service, you can disable the service. Use the taskbar’s Search box to type services, and then click View Local Services. Double-click the problematic service to open its property sheet. In the Startup Type list, select Disabled and then click OK.

If the problem is a Startup item, use Task Manager to disable it. If the item is a program, consider repairing, uninstalling, or reinstalling the program.

If you double-click the problem device to open its properties, as shown in Figure 26.11, the Device Status area tells you a bit more about what’s wrong. As you can see in Figure 26.11, the problem here is that the device drivers aren’t installed. Device Manager usually offers a suggested remedy (such as the Update Driver button shown in Figure 26.11).

Device Manager uses three different icons to give you an indication of the device’s current status:

A black exclamation mark (!) on a yellow field tells you that there’s a problem with the device.

A red X tells you that the device is disabled or missing.

A blue i on a white field tells you that the device’s Use Automatic Settings check box (on the Resources tab) is deactivated and that at least one of the device’s resources was selected manually. Note that the device might be working just fine, so this icon doesn’t indicate a problem. If the device isn’t working properly, however, the manual setting might be the cause. (For example, the device might have a DIP switch or jumper set to a different resource.)

If your system flags a device, but you don’t notice any problems, you can usually get away with just ignoring the flag. I’ve seen lots of systems that run perfectly well with flagged devices, so this falls under the “If it ain’t broke...” school of troubleshooting. The danger here is that tweaking your system to try to get rid of the flag can cause other—usually more serious—problems.

Finish installing the driver—In some cases, a setup program might not be able to complete its driver installation. This can occur if Windows blocks it from accessing certain areas of the system drive or determines that extra software is required for the driver to work. Rather than aborting the install, Windows only lets it go so far and then displays a notification prompting you to let Windows complete the driver installation. In such cases, Control Panel’s Security and Maintenance window shows a Finish Installing Device Software message, as shown in Figure 26.12. Click Install to proceed with the installation.

Reinstall the driver—A driver might be malfunctioning because one or more of its files have become corrupted. You can usually solve this by reinstalling the driver. Just in case a disk fault caused the corruption, you should check the partition where the driver is installed for errors before reinstalling.

Upgrade to a signed driver—Unsigned drivers—that is, device drivers that don’t come with a signature from Microsoft that verifies the drivers are safe to install—are accidents waiting for a place to happen in Windows 10, so you should upgrade to a signed driver, if possible. How can you tell whether an installed driver is unsigned? Open the device’s properties sheet and then display the Driver tab. Signed driver files display a name beside the Digital Signer label, whereas unsigned drivers display “Not digitally signed” instead.

Disable an unsigned driver—If an unsigned driver is causing system instability and you can’t upgrade the driver, try disabling it. In the Driver tab of the device’s properties sheet, click Disable.

Use the Signature Verification tool—This program checks your entire system for unsigned drivers. To use it, click inside the taskbar’s Search box, type sigverif, and press Enter. In the File Signature Verification window, click Start. When the verification is complete, the program displays a list of the unsigned driver files (if any). The results for all the scanned files are written to the log file Sigverif.txt, which is copied to the %SystemRoot% folder when you close the window that shows the list of unsigned drivers. In the Status column of Sigverif.txt, look for files listed as “Not Signed.” If you find any, consider upgrading these drivers to signed versions.

Try the manufacturer’s driver supplied with the device—If the device came with its own driver, either try updating the driver to the manufacturer’s or try running the device’s setup program.

Download the latest driver from the manufacturer—Device manufacturers often update drivers to fix bugs, support new operating system versions, add new features, and tweak performance. Go to the manufacturer’s website to see whether an updated driver is available.

Roll back a driver—If the device stops working properly after you update the driver, try rolling it back to the old driver. (See the next section.)

If updating the driver was the last action you performed on the system, restore the system to the most recent restore point (see “Recovering Using System Restore,” later in this chapter).

If you’ve updated other things on the system in the meantime, a restore point might restore more than you need. In that case, you need to roll back just the device driver that’s causing problems.

Follow these steps to roll back a device driver:

1. Press Windows Logo+X and select Device Manager.

2. Right-click the device and click Properties to open its Properties dialog box.

3. Display the Driver tab.

4. Click Roll Back Driver, and then click OK.

In versions of Windows prior to Windows 8, you could access the advanced startup options by pressing F8 during startup (after your PC completed its Power-On Self Test). That no longer works, but Windows 10 (like Windows 8 and 8.1) offers many other ways to get to the RE and its advanced startup options:

Use the Settings app from within Windows 10.

Use the SHUTDOWN command from within Windows 10.

Use the boot options screen if you dual-boot Windows 10 and another operating system.

Boot to a recovery drive.

Boot to a system repair disc.

Boot to your Windows 10 installation media.

The next few sections discuss each method in more detail.

1. Click Start, and then click Settings to open the Settings app.

2. Click Update & Security.

3. Click the Recovery tab.

4. In the Advanced Startup section, click Restart Now. The Choose an Option screen appears, as shown in Figure 26.13.

5. Click Troubleshoot.

1. Right-click the desktop and then select New, Shortcut. The Create Shortcut dialog box appears.

2. Enter the following in the Type the Location of the Item text box and press Enter:

shutdown.exe /o /r /t 00

3. Type a name for the shortcut and click Finish.

4. Right-click the shortcut and click Properties.

5. Click Change Icon and then click OK when Windows 10 tells you the program contains no icons. Windows 10 displays the icons that come with the shell32.dll file.

6. Select an icon, click OK, and then click OK to close the Properties dialog box.

When you run this shortcut, Windows 10 reboots the system and you end up at the Choose an Option screen. Click Troubleshoot.

For information on setting up your system to dual-boot, see “Dual-Booting Windows 10,” p. 43.

If you dual-boot Windows 10 and other operating systems, follow these steps to boot to the RE:

1. Restart your computer. The Choose an Operating System screen appears.

2. Click Change Defaults or Choose Other Options. The Options screen appears.

3. Click Choose Other Options. The Choose an Option screen appears.

4. Click Troubleshoot.

To learn how to create a Windows 10 recovery drive, see “Creating a Recovery Drive,” p. 748.

Follow these steps to boot to the RE using the recovery drive:

1. Insert the recovery drive.

2. Restart your PC and boot to the USB flash drive:

If you have a newer PC that has a Unified Extensible Firmware Interface (UEFI), Windows 10 will recognize the flash drive automatically and display the Use a Device screen. Click your flash drive in the list that appears.

If you have an older PC that doesn’t support UEFI, you will need to access your PC’s BIOS settings and configure them to boot to the flash drive. Right after you turn on the PC, look for a message that says something like “Press Del to access BIOS/Start settings.” Press the key, and then use the BIOS interface’s boot options to configure your PC to boot to the USB flash drive and disable the Secure Boot feature, if it exists.

3. Click a keyboard layout. The Choose an Option screen appears.

4. Click Troubleshoot.

Follow these steps to boot to the RE using a system repair disc:

1. Insert the system repair disc.

2. Restart your PC and boot to the system repair disc. In most cases, wait until you see a message similar to “Press any key to boot from CD or DVD...” and then press a key. If you don’t see this message, access the PC’s BIOS settings and configure them to boot to the optical drive first and to disable the Secure Boot feature.

3. Click a keyboard layout. The Choose an Option screen appears.

4. Click Troubleshoot.

1. Insert your Windows 10 install media.

2. Restart your PC and boot to the install drive.

3. When the Windows Setup dialog box appears, click Next.

4. Click Repair Your Computer. The Choose an Option screen appears.

5. Click Troubleshoot.

From here, you can reset your PC (we discuss this option later in this chapter; see “Resetting Your PC”). You can also click Advanced Options to display the Advanced Options screen, shown in Figure 26.15.

From here, you can run System Restore (see “Recovering Using System Restore,” later in this chapter), recover a system image (see “Restoring a System Image”), run an automatic repair (see “Automatically Repairing Your PC”), access the Command Prompt to use its command-line tools, or revert to an earlier build of Windows 10.

In most cases, you can also click Startup Settings and then click Restart to access even more startup settings. (Note that you don’t see the Startup Settings option if you boot to a recovery drive, a system repair disc, or the Windows 10 install media.) Windows 10 restarts your PC and displays the Startup Settings screen, shown in Figure 26.16.

Press Enter to load Windows 10 in the usual fashion. You can use the other options to control the rest of the startup procedure:

Enable Debugging—This command enables remote debugging of the Windows 10 kernel.

Enable Boot Logging—This option is the same as the Boot Normally option, except that Windows 10 logs the boot process in a text file named ntbtlog.txt that resides in the system root.

Enable Low-Resolution Video—This option loads Windows 10 with the video display set to 640×480 and 256 colors. This is useful if your video output is garbled when you start Windows 10. For example, if your display settings are configured at a resolution that your video card can’t handle, boot in the low-resolution mode and then switch to a setting supported by your video card.

Enable Safe Mode—The three Safe Mode options enable you to run a barebones version of Windows 10 for troubleshooting. See “Booting Up in Safe Mode,” later in this chapter.

Disable Driver Signature Enforcement—This item prevents Windows 10 from checking whether device drivers have digital signatures. Choose this option to ensure that Windows 10 loads an unsigned driver, if failing to load that driver is causing system problems.

Disable Early Launch Anti-Malware Driver—This option prevents Windows 10 from scanning device drivers for malware during startup. If Windows 10 won’t start, it’s possible that the anti-malware scan is messing with a driver.

Disable Automatic Restart After Failure—This option prevents Windows 10 from restarting automatically when the system crashes. Choose this option if you want to prevent your system from restarting so that you can read an error message or deduce other information that can help you troubleshoot the problem.

You can also press F10 and then press 1 to launch the RE from here.

When you start in Safe mode, Windows 10 uses the all-powerful Administrator account, which is the account to use when troubleshooting problems. However, caution is required when doing so.

When Windows 10 finally loads, as shown in Figure 26.17, the desktop reminds you that you’re in Safe mode by displaying “Safe Mode” in each corner.

You should use the Safe mode option if one of the following conditions occurs:

Windows 10 doesn’t start after the POST ends.

Windows 10 seems to stall for an extended period.

You can’t print to a local printer.

Your video display is distorted and possibly unreadable.

Your computer stalls repeatedly.

Your computer suddenly slows down and doesn’t return to normal without a reboot.

You need to test an intermittent error condition.

You should use the Safe Mode with Networking option if one of the following situations occurs:

Windows 10 fails to start using any of the other Safe mode options.

The drivers or programs you need to repair a problem exist on a shared network resource.

You need access to email or other network-based communications for technical support.

You need to access the Internet via your network to download device drivers or visit an online tech support site.

Your computer is running a shared Windows 10 installation.

Windows 10 fails to start using any of the other Safe mode options.

The programs you need to repair a problem must be run from the Command Prompt.

You can’t load the Windows 10 GUI.

1. Press Windows Logo+X, click Command Prompt (Admin), and then enter your User Account Control credentials.

2. At the command line, type the following command and press Enter (this tells BCDEdit to write your PC’s boot info to a file named boot.txt on your desktop):

Click here to view code image

bcdedit /enum /v > %userprofile%desktopoot.txt

3. Leave Command Prompt open and double-click the boot.txt file on your desktop to open the file in Notepad.

4. In the Windows Boot Loader section, copy the identifier value (including the opening and closing braces).

5. Return to Command Prompt and type bcdedit /copy followed by a space.

6. Press Ctrl+V to paste the identifier value you copied in step 4.

7. Type a space followed by /d "Windows 10 (Safe Mode)" and then press Enter. BCDEdit copies the boot info to the new entry.

8. In the taskbar’s Search box, type msconfig and then press Enter to start the System Configuration tool.

9. In the Boot tab, click the Windows 10 (Safe Mode) boot item you just created.

10. Select the Safe Boot check box, as shown in Figure 26.18.

11. Click OK.

Your next step should be the RE’s Startup Repair option, which attempts various repair strategies that are often useful for getting a PC back on its feet. Here’s how to use it:

1. Boot to the RE, as described earlier (see “Accessing the Recovery Environment”).

2. Click Advanced Options. The Advanced Options screen appears.

3. Click Startup Repair. (If you’re running the command from a recovery disk or your install media, you’re prompted to select the target operating system, which will be Windows 10.) Windows 10 reboots and Startup Repair prompts you for your user account.

4. Click your user account. Automatic Repair prompts you for your password.

5. Type your account password and then click Continue. Automatic Repair begins the repair process.

You revert Windows 10 to an earlier configuration by using System Restore. We show you how to use System Restore to set restore points in Chapter 32, “Protecting Your Data from Loss and Theft.”

To learn how to create a restore point, see “Setting System Restore Points,” p. 746.

To revert your system to a restore point, follow these steps:

1. Launch System Restore:

If you can boot Windows 10—In the taskbar’s Search box, type restore, click Create a Restore Point in the search results, and then click System Restore.

If you can’t boot Windows 10—Boot to the RE, as described earlier (see “Accessing the Recovery Environment”), click Advanced Options, and then click System Restore.

2. In the initial System Restore dialog box, click Next. System Restore displays a list of restore points.

3. If you don’t see the restore point you want to use, click to activate the Show More Restore Points check box, which tells Windows 10 to display all the available restore points.

4. Click the restore point you want to use. There are seven common types of restore points:

System—A restore point that Windows 10 creates automatically. For example, the System Checkpoint is the restore point that Windows 10 creates each day or when you boot your computer.

Critical Update—A restore point set prior to installing an important update.

Install—A restore point set prior to installing a program or optional update.

Uninstall—A restore point set prior to uninstalling a program or update.

Manual—A restore point you create yourself.

Undo—A restore point set prior to a previous use of System Restore to revert the system to an earlier state.

Unknown—Any restore point that doesn’t fit in the preceding categories.

5. Click Next. If other hard disks are available in the restore point, Windows 10 displays a list of the disks. Activate the check box beside each disk you want to include in the restore and then click Next.

6. Click Finish. Windows 10 asks you to confirm that you want your system restored.

7. Click Yes. System Restore begins reverting to the restore point. When it’s done, it restarts your computer and displays a message telling you the results of the restore.

8. Click Close.

Here are the steps to follow to reset your PC:

1. Launch Refresh Your PC:

If you can boot Windows 10—Click Start, then Settings, and then Update & Security. Click the Recovery tab, and then click Get Started under Reset This PC.

If you can’t boot Windows 10—Boot to the RE’s Troubleshoot screen, as described earlier (see “Accessing the Recovery Environment”) and click Reset This PC. Windows 10 reboots the PC and asks you to choose your user account. Click your user account, type your account password, and then click Continue.

2. Click Keep My Files. Reset This PC displays a list of the desktop programs you’ll need to reinstall.

3. Make a note of the programs, and then click Next.

4. Click Reset. Refresh Your PC reboots the computer and runs the refresh.

To learn how to create a system image, see “Setting System Restore Points,” p. 746.

Follow these steps to restore a system image:

1. If you saved the system image to an external hard drive, connect that hard drive. If you used DVDs, insert the last DVD in the set.

2. Boot to the RE, as described earlier (see “Accessing the Recovery Environment”).

3. Click Advanced Options. The Advanced Options screen appears.

4. Click System Image Recovery. Windows 10 prompts you to choose a user account.

5. Click your user account, type your password, and then click Continue. System Image Recovery prompts you to select a system image backup and offers two options:

Use the Latest Available System Image—Activate this option to restore Windows 10 using the most recently created system image. This is almost always the best way to go because it means you’ll restore the maximum percentage of your data and programs. If you choose this option, click Next and skip to step 8.

Select a System Image—Activate this option to select from a list of restore points. This is the way to go if you saved a system image to your network, or if the most recent system image includes some change to your system that you believe is the source of your system problems. Click Next and continue with step 6.

6. Click the location of the system image and then click Next.

7. Click the system image you want to use for the restore and then click Next. If you want to use a system image saved to a network share, click Advanced and then click Search for a System Image on the Network.

8. If you replaced your hard drive, activate the Format and Repartition Disks check box.

9. Click Next. System Image Recovery displays a summary of the restore process.

10. Click Finish. System Image Recovery asks you to confirm.

11. Click Yes. System Image Recovery begins restoring your computer and then reboots to Windows 10 when the restore is complete.