msosync.exe

What is msosync.exe?

msosync.exe is the executable for the Microsoft Office Shared Sync Service. It coordinates data syncing for Office apps, SharePoint, and OneDrive, often creating a background process per synchronization task to keep documents up to date.

This design enables seamless cross-device collaboration. It runs in sandboxed processes to isolate sync work from the UI, reducing UI freezes while uploading, downloading, or reconciling changes.

Types of msosync Processes

• Sync Manager Process: Coordinates overall sync tasks and user prompts (1 instance)
• SharePoint/OneDrive Renderer: Handles data transfer for specific libraries (multiple)
• Background Indexer: Indexes changes and prepares delta uploads
• Conflict Resolver: Manages version conflicts during sync
• Notification Handler: Delivers sync status alerts to the UI
• Telemetry Utility: Gathers usage metrics for diagnostics

Is msosync.exe Safe?

Yes, msosync.exe is safe when it's the legitimate file from Microsoft Office downloaded from official sources.

Is msosync.exe a Virus or Malware?

The real msosync.exe is NOT a virus. However, malware sometimes disguises itself using similar names to trick users.

How to Tell if msosync.exe is Legitimate or Malware

1. File Location:: Must be in C:\Program Files\Microsoft Office\Office16\ or C:\Program Files (x86)\Microsoft Office\Office16\. Any msosync.exe elsewhere is suspicious.
2. Digital Signature:: Right-click the process in Task Manager → Open file location → Right-click msosync.exe → Properties → Digital Signatures. Should show "Microsoft Corporation".
3. Resource Usage:: Normal usage is 1-10% CPU across the system and 30-150 MB memory for typical Office sync tasks.
4. Behavior:: Msosync.exe should run when Office sync tasks are active. If it runs constantly without Office apps, consider malware check.

Why Is msosync.exe Running on My PC?

msosync.exe runs to coordinate synchronization tasks for Office apps, SharePoint, and OneDrive, ensuring data is up to date across devices. It can run on demand or in the background depending on user settings and Office activity.

Reasons it's running:

• Active Office Sync Sessions: Office apps like Word/Excel trigger synchronization with OneDrive/SharePoint, spawning msosync for data transfer.
• Background Sync Tasks: Background tasks such as autosave, version history, and cloud sync may run msosync to maintain data integrity.
• Startup Services: Office-related services can start msosync at user login to enable immediate readiness.
• Device Synchronization: Cross-device sync across Office apps requires msosync to keep local and cloud copies in sync.
• Offline-to-Online Transitions: When you reconnect after being offline, msosync coordinates data reconciliation between local Office files and cloud storage.

Can I Disable or Remove msosync.exe?

Yes, you can disable msosync.exe. It is safe to close Office apps; disabling may affect sync features across devices, but you can re-enable later.

How to Stop msosync.exe

• End Office Sync Tasks: In Task Manager, locate msosync.exe or related Office sync tasks and end them.
• Close Office Apps: Exit Word, Excel, PowerPoint, and any Office apps.
• End All msosync Processes: Open Task Manager → Details tab → end all msosync.exe processes.
• Disable Startup: Task Manager → Startup tab → Disable Microsoft Office Sync (msosync) or related Office services.
• Adjust Sync Settings: Office apps or OneDrive settings → disable automatic sync if desired.

How to Uninstall Office or Disable Sync Features

• ✔ Windows Settings → Apps → Apps & Features → Microsoft Office → Change → Add/Remove Features to disable specific sync components
• ✔ Control Panel → Programs → Uninstall a program → Microsoft Office → Uninstall
• ✔ Consider using a different workflow: use offline mode or alternative tools

Common Problems: High CPU or Memory Usage

If msosync.exe is consuming excessive resources:

Common Causes & Solutions

• Active Sync on Many Documents: Limit active documents or pause sync in Office/OneDrive to reduce load.
• Background Sync Extensions: Disable or configure sync in Office settings to limit background tasks.
• Outdated Office Version: Update Office to the latest version via Windows Update or Office update.
• Conflicts with Antivirus: Ensure antivirus isn't scanning msosync too aggressively; add exclusions.
• Corrupted Office Profile: Repair Office installation from Apps & Features.
• Malware Masquerading: Run a full malware scan and verify path against official Office directory.

Related Processes