When critical Windows system files are missing or corrupted, some Windows features may stop working correctly or Windows may stop responding altogether. If this happens, you can use the Deployment Image Servicing and Management tool (DISM) and the System File Checker tool (SFC) to scan your system files and restore any corrupted or missing files.

First, you'll need to download the troubleshooter. Download troubleshooter. If you see the File Download box when you start downloading, select Run or Open. The troubleshooter provides steps for you to follow. If a program isn't listed in the uninstall options, you'll be asked for that program's product code.

Get Help has troubleshooters you can run for many common scenarios. These often help resolve issues without the need to contact support. If a troubleshooter is available for your issue, select Run to start that troubleshooter.

For the most complete scan, run Microsoft Defender Offline. For more about that see Help protect my PC with Microsoft Defender Offline. Select the type of scan you want to run, then Start scan. When the scan completes, Defender will tell you if it found anything. When would I want to run a scan?

PC Health Check app brings you up to date info on your Windows device health, helping you take action to improve your device performance and troubleshoot performance problems. It is periodically updated based on customer feedback to help you make the most of your Windows PC. How to open PC Health Check.

Learn how to uninstall and reinstall OneDrive.

Follow these steps to automatically diagnose and repair Windows security problems by turning on UAC, DEP protection, Windows Firewall, and other Windows security options and features. Select the Download button on this page. In the File Download dialog box, click Run or Open, and then follow the steps in the Windows Security Troubleshooter. Notes:

Use the Microsoft 365 shared computer activation (SCA) troubleshooter to enable shared computer activation for Microsoft 365 applications. Use the MIcrosoft 365 inventory scan troubleshooter to generate either a normal or full scan report of your computer and installed Microsoft 365 applications.

Fixes a crash issue that occurs when a cluster node sends a message that is larger than 64 KB to another cluster node after the two nodes reconnect. This issue occurs in Windows Server 2012 R2.

To obtain the current version of Windows Security app, please run powershell command below: Get-AppPackage Microsoft.SecHealthUI. Manually download the update. 64-Bit | ARM64. More about Windows Security app here.