The new operating system might be a step up from previous versions in a lot of ways, but Windows 10 boot problems still pop up that it cannot fix on its own.
There are a number of steps you can take if a Windows 10 computer fails to boot properly, as long as you know what tools to use and where to find them.
Four of the top approaches for solving Windows 10 boot problems are launching the Startup Repair tool, repairing the Master Boot Record (MBR), scanning the system for corrupt or missing files, and running the Deployment Image Servicing and Management (DISM) tool.
Running Startup Repair
The Startup Repair tool scans a system for corrupt or missing files, as well as improperly configured settings, and then it attempts to repair them.
To launch the tool, go to the Advanced Options screen and click Startup Repair. You might have to confirm which administrator account to use and provide a password.
If Startup Repair can fix the Windows 10 boot problems, it does so automatically. If it cannot, you should receive a message that it could not repair the PC. In such cases, use the advanced repair options to launch the command prompt window and open the Startup Repair log file in Notepad, which is available in recovery mode. The following path shows the directory and file name:
%WinDir%\System32\LogFiles\Srt\SrtTrail.txt
The file shows you where the Startup Repair tests failed. From there, you can use the other advanced tools to address any issues.
Repairing the Master Boot Record
The MBR is a data structure within a partition that allows a computer to find and load the OS on startup. If the MBR is corrupted, Windows 10 won't boot properly.
You can use the Windows bootrec utility to repair the MBR. To do so, launch the command prompt window from the Advanced Options screen and then run the bootrec utility like you would any other command-line utility, using the following syntax:
bootrec /<option>
You can run most of the utilities Windows supports with the command prompt window in recovery mode.
When you run bootrec /<option>, replace the <option> placeholder with one of the following:
Use fixmbr to write the MBR to the system partition, without overwriting the existing partition table, and resolve MBR corruption issues or remove nonstandard code from the MBR.
Use fixboot to write a new boot sector to the partition if the boot sector is damaged, has been replaced with a nonstandard boot sector or if an earlier Windows OS is installed.
Use scanos to scan all disks for installations not compatible with Windows 10 if the Boot Manager does not list a Windows installation.
Use rebuildbcd to rebuild the boot configuration data store when you must completely rebuild the store.
Repairing corrupted system files
You can run most of the utilities Windows supports with the command prompt window in recovery mode. If bootrec doesn't work, try system file check (sfc).
The sfc utility checks for system files that might be corrupt, missing or in some other way problematic. The utility automatically replaces the corrupt or missing files with the correct ones. To use sfc to scan a system, open the command prompt window and run sfc /scannow.
You might need to navigate to the %WinDir%\System32\ folder to run sfc. You might also need to run sfc several times to ensure that it catches all issues. If after all this you receive a message stating that some corrupt files could not be repaired, it's time to use the DISM tool.
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Running the DISM tool
Like bootrec and sfc, the DISM tool is a command-line utility, dism. You can use DISM to mount and service Windows images, including Windows image files and virtual hard disks. The DISM tool comes with Windows and is also distributed as part of the Windows Assessment and Deployment Kit. In addition to configuring Windows features and settings, you can use DISM to repair a Windows image, both offline and online.
Consider using the DISM tool even if the sfc utility does not uncover any issues. To use DISM, launch the command prompt window and enter the dism command using dism /<option> [/<option> ...].
You can include one or more options when calling the dism utility. The primary options include the following:
Use checkhealth to verify whether the image has been flagged as corrupted and whether the image can be repaired.
Use scanhealth to search for component store corruption.
Use cleanup-image to perform a cleanup or recovery operation on the image.
Use restorehealth to search for component store corruption and then try to automatically repair the image.
DISM also supports several options for specifying where to find the offline image or whether to run the utility against an online image. For example, the following command searches for component store corruption and performs a cleanup operation on a running instance of Windows 10:
dism /online /cleanup-image /scanhealth
Other advanced repair options
Other repair options for Windows 10 boot problems include using the Reset This PC option on the troubleshoot screen to reinstall Windows, either retaining personal files or deleting them.
You could also use the System Restore option in Advanced Options to return Windows to a specific restore point or the System Image Recovery option to restore a previously saved image. From the Advanced Options screen, you can also try the Startup Settings option to launch the system in safe mode or use the Go Back to the Previous Build option to return to the last build.
