The Windows Repair Command I Forget Until I Need It: sfc

Every so often, Windows starts acting weird. Not broken enough to fail outright, but flaky enough to waste your time: settings won’t open, built-in tools misbehave, updates half-work, or things just feel off.

Before reinstalling Windows, reimaging a machine, or going down a rabbit hole of guesswork, it’s worth remembering a command that’s been around forever:

sfc /scannow

System File Checker does exactly one job: it verifies the integrity of core Windows system files and replaces corrupted ones with known-good versions. That’s it. No magic, no tuning, no knobs to turn.

Why it’s worth running:

• It’s built into Windows
• It’s safe
• It’s fast compared to a reinstall
• It fixes a surprising number of “how did Windows even get into this state?” problems

What it won’t do:

• Fix drivers
• Fix third-party software
• Fix hardware
• Fix deep image corruption

If sfc reports it can’t repair everything, that’s usually a sign the Windows image itself is damaged. At that point, DISM /Online /Cleanup-Image /RestoreHealth comes next, followed by another sfc /scannow.

This isn’t advanced troubleshooting. It’s basic hygiene. And yet it’s easy to forget until you’re already frustrated.

So this is the reminder:
When Windows misbehaves and there’s no obvious cause, run sfc /scannow early—not as a last resort.