When Windows keeps throwing errors or features behave strangely, you don't have to jump straight to a reset. Windows includes several repair tools, and the gentlest ones don't touch your files at all. Here they are from least to most drastic. Back up anything important before you start.
1. Run DISM, then SFC
SFC (System File Checker) finds damaged or modified Windows system files and replaces them with good copies. DISM repairs the component store that SFC uses as its source. Microsoft recommends running DISM first.
- Search for cmd in the Start menu and choose Run as administrator.
- Run these two commands, one after the other:
DISM /Online /Cleanup-Image /RestoreHealth
sfc /scannow2. Why DISM comes first
SFC repairs files using copies stored inside Windows. If that store is itself damaged, SFC can't finish the job. DISM /RestoreHealth repairs the store, pulling clean files from Windows Update, so stay connected to the internet while it runs. It often seems to sit at around 20% for a long time; that's normal, so let it finish.
Reading SFC results
| Message | What it means |
|---|---|
| Did not find any integrity violations | System files are fine |
| Found corrupt files and successfully repaired them | Fixed. Restart the PC |
| Found corrupt files but was unable to fix some of them | Run DISM again, then SFC once more |
3. CHKDSK for file system errors
If you suspect disk errors, check the drive:
chkdsk C: /scanscans online while you keep working.chkdsk C: /ffixes errors. Because C: is in use, it asks to run at the next restart. Type Y and restart.chkdsk C: /ralso looks for bad sectors. On hard drives this can take hours.
For the drive's physical health and SSD wear, see our disk health guide.
4. Windows 11: reinstall the current version
Go to Settings > System > Recovery > Fix problems using Windows Update and select Reinstall now. Windows reinstalls itself while keeping your files, apps and settings. If command lines aren't your thing, this is the easiest repair.
5. Use the recovery environment
If Windows starts, go to Settings > System > Recovery and select Restart now next to Advanced startup. You can also hold Shift while choosing Power > Restart from the sign-in screen. If Windows can't start at all, it usually opens recovery on its own after a few failed boots.
Under Troubleshoot > Advanced options you'll find:
- Startup Repair: fixes problems that stop Windows from loading.
- System Restore: rolls back to an earlier restore point without touching personal files. See our System Restore guide.
- Uninstall Updates: removes the latest quality or feature update.
- Startup Settings: lets you boot into Safe Mode.
- Command Prompt: run chkdsk and other tools outside Windows.
6. Last resort: reset the PC
If nothing above helps, go to Settings > System > Recovery > Reset this PC and choose Keep my files. You'll need to reinstall apps afterwards. For a completely clean install, see our Windows 11 install USB guide.
FAQ
SFC says I need to be an administrator.
You opened Command Prompt normally. Close it and reopen it with Run as administrator.
DISM fails with error 0x800f081f.
It couldn't find repair source files. Check your internet connection and retry, or use the Windows 11 reinstall option in step 4.
Will these commands delete my files?
No. SFC, DISM and CHKDSK work on system files and disk structures, not your documents. If the drive is close to failing, though, heavy scans add strain, so back up first.
Do these work on Windows 10?
Yes. DISM, SFC, CHKDSK and the recovery environment all work on Windows 10. The "Fix problems using Windows Update" option is Windows 11 only.