PROCESSMicrosoft-signed
TiWorker.exeWindows Modules Installer Worker
Windows Modules Installer Worker, the process TiWorker.exe, installs, changes and removes Windows updates and optional features on behalf of the Windows Modules Installer service. High CPU and disk usage from it is normal while updates are being checked or installed and should subside afterwards. Persistent high usage usually means a stuck update.
What it does
Windows Modules Installer Worker (TiWorker.exe) is the worker process of the Windows Modules Installer service, also known as TrustedInstaller. Together they install, modify and remove Windows updates and optional Windows features, and they maintain the component store (WinSxS) that sfc and DISM draw on. Because only TrustedInstaller has permission to change protected system files, this is the process that does the heavy lifting during Windows servicing.
Why it uses so much CPU and disk
Installing updates means expanding packages, replacing system files, updating the component store and verifying integrity, all disk- and CPU-intensive. High usage is therefore expected:
- Around Patch Tuesday (the second Tuesday each month) and for a while afterward.
- After a feature update or a large cumulative update.
- During scheduled automatic maintenance, often when the PC is idle.
It should return to idle once servicing completes.
When it is a problem
If TiWorker.exe runs high for days rather than hours, an update is likely stuck:
- Run the Windows Update troubleshooter (Settings → System → Troubleshoot).
- Repair the component store, then the system files:
DISM /Online /Cleanup-Image /RestoreHealth
sfc /scannow- Reset the update cache: stop the Windows Update service, delete the contents of
C:\Windows\SoftwareDistribution\Download, restart the service, and check for updates again. - Let automatic maintenance run overnight rather than fighting it during the day. You can adjust active hours so restarts do not interrupt you.
Setting the Windows Modules Installer service (sc or services.msc) to manual stops it running unprompted, at the cost of updates not installing on their own. Do not delete or permanently disable it.
Confirming it is genuine
TiWorker.exe legitimately runs from within the C:\Windows\WinSxS component store, not from a user folder, and is signed by Microsoft. Because its path is buried in WinSxS, use Task Manager's Open file location to confirm it resolves under C:\Windows\WinSxS and check the Microsoft signature.
Frequently asked questions
Why is Windows Modules Installer Worker using 100% disk or CPU?
It is checking for, downloading or installing updates, or servicing the component store. This is expected around Patch Tuesday and after feature updates. Let it finish; it usually settles within an hour or two. If it runs high for days, an update is stuck.
Can I stop or disable it?
You can set the Windows Modules Installer service to manual, which stops it running unprompted, but updates will not install until you run them. It is better to let it complete than to disable it. Never delete TiWorker.exe.
How do I fix it when it never stops?
Run the Windows Update troubleshooter, then repair the component store with DISM /RestoreHealth and sfc /scannow. Clearing the SoftwareDistribution folder after stopping the update service also helps a stuck update.