FileCoAuth.exe
Also called filecoauth, file co-authoring, onedrive file co-authoring
Office file co-authoring and sync lock helper for OneDrive and SharePoint. It coordinates who holds the file. It is not WINWORD.EXE.
What you need to know
FileCoAuth is co-authoring lock helper, not WINWORD itself.
FileCoAuth.exe manages co-authoring locks for Office files on OneDrive and SharePoint. WINWORD.EXE still edits the document. A burst of short FileCoAuth rows is often COM embedding, not a second Word.
- Safe?
- Yes, with Office and OneDrive
- Is it Word?
- No. This is the lock helper
- Many short copies?
- COM launch, then it can exit
What is FileCoAuth.exe?
FileCoAuth.exe is the co-authoring lock helper, not WINWORD.EXE. It lives next to the OneDrive client on many PCs, and Office can start it when a cloud document needs a lock.
What does it do?
It coordinates sync locks so two people can edit one cloud file. It does not draw the Word ribbon. OneDrive.exe still owns the tray.
Why is it running?
A Word, Excel, or PowerPoint file on OneDrive or SharePoint is open, or Office probed the lock. Short-lived copies with -Embedding are common.
Why are there multiple copies?
Several short FileCoAuth.exe rows can be separate COM activations. None of those copies is a second WINWORD.EXE.
Is it safe?
Usually safe
A Microsoft-signed FileCoAuth under the OneDrive version folder or Office16 is the helper. A FileCoAuth.exe in Temp is not. This is still not Word.
A legitimate copy normally runs from:
C:\Users\<you>\AppData\Local\Microsoft\OneDrive\<version>\FileCoAuth.exe
- Also seen under Microsoft Office\root\Office16
- Often started with -Embedding
- Not WINWORD.EXE
Can I end it?
Cloud file locks can fail
Ending FileCoAuth.exe can drop a co-authoring session. The document window is still WINWORD.EXE. Save in Word if the UI still responds.
Can I remove it?
Unlink OneDrive or uninstall Office
Do not delete FileCoAuth.exe. Stop using cloud co-authoring by working on a local copy, or unlink OneDrive. Deleting WINWORD does not remove this helper.
Should it start with Windows?
Office or OneDrive starts it on demand. It is not a Startup Apps entry named FileCoAuth.
Normal resource behavior
These are contextual labels, not universal averages.
- CPU
- Usually a short burst when a cloud Office file opens
- Memory
- Small
- Disk
- Low
- Network
- OneDrive or SharePoint lock traffic
File information
| Executable name | FileCoAuth.exe |
|---|---|
| Common legitimate path | C:\Users\<you>\AppData\Local\Microsoft\OneDrive\<version>\FileCoAuth.exe |
| Publisher | Microsoft Corporation |
| Signature expectation | Signed by Microsoft Windows |
Common problems
Many processes scare people
COM can start a helper per document probe. That is not a Word clone farm. Check how long each row lives.
File is locked after someone killed the helper
Close the Office app, then reopen the cloud file. Do not delete WINWORD to clear a SharePoint lock.
Troubleshooting
Diagnose before you change anything destructive.
Close the Office document, then reopen from OneDrive
That restarts the lock helper cleanly. Ending WINWORD mid-edit risks the buffer.
Confirm the path is OneDrive or Office16
AppData\Local\Microsoft\OneDrive or Office16 is this article. A FileCoAuth.exe on the desktop is a different file.
Technical details
Technical details
| Image name | FileCoAuth.exe |
|---|---|
| Role | Office / OneDrive co-authoring lock helper |
Sources and verification
Reviewed by Feex editorial. Last verified August 2026 Status: Feex Reviewed. How we research.
- Microsoft Support: real-time co-authoring · Co-authoring is an Office plus OneDrive or SharePoint feature
- Microsoft Support: OneDrive · Sync client hosts FileCoAuth on many PCs
- Foxhole process map · First-party samples on Windows PCs. Not a lab benchmark.
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