Windows Troubleshooting / Windows Update
How to Fix a Windows Update That Failed to Install
Quick answer
Read the exact error in Settings → Windows Update. If the disk is nearly full, free space first. Restart once, then Retry. If checking never finishes at all, that is [stuck checking](/guides/windows-update-stuck-checking), not this page. Look up a hex code in the [Error Code Lookup](/tools/error-code-lookup). Skip third-party "update repair" installers.
Quick diagnosis
If several of these match what you see, you are in the right guide.
- Windows Update shows an error after a download
- The PC restarts, then says undoing changes
- A hex code such as 0x80070070 or 0x800F0922
- The same update fails every time
Possible causes
- Not enough free disk space
- A corrupted download payload
- A pending restart that never completed cleanly
- The update service or cache is in a bad state
- A driver or language pack conflicting with that particular KB
What you need
- Settings → Windows Update
- Several gigabytes free on C:
What this problem usually means
Checking, downloading, and installing are three stages. A failure at install means Windows already talked to Microsoft and still could not apply the package. Retrying without space or after a dirty shutdown repeats the same failure.
Before you start
- Plug the laptop in. Write down the error code exactly.
- If this is a work PC, stop and ask IT, they may push patches their own way.
- Do not download a Windows ISO from an ad to "slipstream" the update.
Quick fixes
1. Space, restart, Retry
- This PC: C: needs several gigabytes free (feature updates need more). Use free disk space.
- Restart from Start so no other install is half-done.
- Settings → Windows Update → Retry or Check for updates.
2. Windows Update troubleshooter
Settings → System → Troubleshoot → Other troubleshooters → Windows Update. Apply what it offers. If it claims success and the same KB still fails, the troubleshooter is not the whole fix.
Step-by-step troubleshooting
Match the code to a known class
0x80070070 is usually disk full. 0x800F0922 often relates to a reserved partition that is too small or a VPN interfering, do not format the recovery partition from a forum screenshot. Use the error lookup for the codes this site documents, then official Microsoft support for the rest. Guessing a registry wipe from a social post is how installs get worse.
Pause other installers
Close Store downloads, game launchers, and vendor "support assistants" that install drivers at the same time. One package manager at a time.
Install from the Microsoft Update Catalog, optional, official
If Settings keeps failing on one KB, Microsoft's Update Catalog can provide that standalone package. You need the KB number from Windows Update history. This is an advanced path. It is still Microsoft. It is not a bundle site named "driverpack."
After a rollback at boot
"Undoing changes" means the update started and Windows backed out. Let it finish. Then free space and retry. If rollback loops into Automatic Repair, treat it as a boot problem, not another Settings click.
Where did Update fail?
Choose an answer. The next question appears below, no account or download required.
Leave this article. Use Windows Update stuck checking.
Free space, restart, Retry. Read the hex code. Avoid unofficial repair tools.
That is stuck restarting. Come back here once you have a desktop.
How to know the problem is fixed
Windows Update history shows the KB succeeded, and a later Check for updates does not immediately re-offer the same failed package. Restart once more to confirm there is no leftover "restart required" hang.
If the problem continues
An in-place repair using official Windows 11 installation media can apply updates as part of repairing system files. Back up first. If every cumulative update fails and the disk reports errors, stop patching and check the drive.
When this may be hardware failure
Repeated install failures plus copy errors or SMART warnings make a failing SSD more likely. Update cannot finish on a volume that cannot write. Confirm with drive health.
Common mistakes to avoid
- Using a third-party Windows Update "agent."
- Deleting the SoftwareDistribution folder as the first click (it can help later; it is not step one).
- Ignoring a disk-full code and retrying overnight.
Frequently asked questions
Should I hide the update?
Microsoft's old "show or hide updates" troubleshooter is a last resort when a specific driver-class update breaks hardware. Hiding a security cumulative update is not a fix. Prefer space and a clean retry.
Can I skip this month's patch?
You can pause updates briefly in Settings. That is a delay, not a repair. Do not pause indefinitely to avoid one error code.
Written by Practical PC editorial team. We write practical Windows and PC troubleshooting guides for home users, students, and office workers. Guides are researched from official documentation and widely observed support patterns, then reviewed for safety and plain language. We do not invent lab tests, certifications, or first-hand repair experience we do not have.