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.

For the most complete scan, run Microsoft Defender Offline. For more about that see Help protect my PC with Microsoft Defender Offline. 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.

Startup Repair is a Windows recovery tool that can fix certain system problems that might prevent Windows from starting. It scans your computer for the problem and then tries to fix it so your computer can start correctly.

This article describes the security and cumulative update for 3.5, 4.8 and 4.8.1 for Windows 10 Version 22H2. Security Improvements. This security update addresses a remote code execution vulnerability detailed in CVE-2025-21176. Quality and Reliability Improvements.

Protect your Android, iPhone, Mac, and Windows devices from threats by installing Microsoft Defender. Download Microsoft Defender on your devices either by: We encourage you to install Microsoft Defender on at least five devices per person. Ready to give it a try?

Download and install the PC Health Check app. The PC Health Check app can be downloaded from the following link: Right-click on the Start menu and select Search . Under Best match, select PC Health Check from the list of results. In the PC Health Check windows that opens, select the Check now button.

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.

Use the command recdisc.exe. Once the repair disc is created, you can use it to boot your computer and access the recovery options, even if your system is unable to start normally.

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.