OneDrive Error Codes

Fix OneDrive File-in-Use and Changing Lock File Errors on Windows 11

Maira Mehtab Sep 22, 2026 869 views

Question details

Users are experiencing persistent synchronization issues where OneDrive reports a file is currently in use without identifying it.

Product: Microsoft OneDrive
Device & OS: Windows 11
Scenario: Syncing local files and folders to the cloud using the OneDrive desktop application.
Observed behavior: OneDrive displays a 'file-in-use' error message alongside constantly changing '.lock_#' synchronization errors, failing to specify which exact file is causing the lock.

Before you start

Verify that your important documents are safely accessible via the OneDrive web interface or copied to a local offline folder before adjusting your synchronization settings.

Solution 1Recommended

Review and Adjust OneDrive Folder Backup Settings

Managing your folder backup settings can help bypass lock errors caused by active system files or background applications.

Sometimes, OneDrive attempts to sync folders containing active system files or application configurations, triggering persistent lock errors. Disabling PC folder backup temporarily can isolate the issue.

Open OneDrive Settings

Click the OneDrive cloud icon located in the Windows 11 taskbar notification area, then click the 'Help & Settings' gear icon and select 'Settings'.

Access Backup Options

Navigate to the 'Sync and backup' tab on the left sidebar, then click the 'Manage backup' button.

Modify Folder Backup

Review the folders currently being backed up (such as Desktop, Documents, or Pictures). Toggle off the backup for these folders to see if the sync error clears, but only after ensuring your files are safely stored.

Solution 2

Unlink and Relink Your OneDrive Account

Unlinking your PC and signing back in refreshes your connection and can clear persistent synchronization loops.

Solution 3

Contact Microsoft Support for Assistance

If local troubleshooting steps do not resolve the changing .lock_# errors, escalate the issue to Microsoft Support.

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Frequently Asked Questions

What does a changing .lock_# error mean in OneDrive?

A .lock error indicates that a file is currently open in another program, or a background process is preventing OneDrive from uploading or downloading it. The number represents a temporary tracking file generated during the failed sync attempt.

Will unlinking my PC from OneDrive delete my local files?

No, unlinking your PC from OneDrive only stops the synchronization process. All files that have already been downloaded to your local hard drive will remain exactly where they are.

How can I find out which file is causing the file-in-use error?

Click the OneDrive icon in the Windows taskbar to open the sync activity list. If the specific file isn't listed, open your OneDrive folder in File Explorer and look for items marked with a red 'X' status icon.

Can I use WPS Office to edit files stored in my OneDrive folder?

Yes. You can easily open, edit, and save documents located in your local OneDrive folder using WPS Office. Changes will automatically be detected and synced by the OneDrive client in the background.

Microsoft Office Error Codes