Sync Error
Microsoft SharePoint / OneDrive
Severity: ModerateWhat Does This Error Mean?
SharePoint sync errors mean your files are not syncing between your computer and SharePoint. This happens when OneDrive (which handles SharePoint sync) runs into a conflict or connection problem. Most sync errors show a red X on the OneDrive icon in the taskbar. Restarting OneDrive and resolving file conflicts fixes the majority of sync errors.
Affected Models
- SharePoint Online
- OneDrive for Business
- Microsoft 365 Business
- Microsoft 365 Enterprise
- SharePoint Server 2019
Common Causes
- A file name contains characters not allowed by SharePoint (such as # % & or special characters)
- A file path is too long — SharePoint has a 400-character limit on the full file path
- Two users edited the same file simultaneously, creating a sync conflict
- OneDrive has lost its authentication token and needs to be signed in again
- A file is locked open by another application and cannot be synced while in use
How to Fix It
-
Check the OneDrive icon in the Windows taskbar. Click it to see which files are failing to sync. The sync panel shows a red icon and the specific file or folder causing the error.
The OneDrive sync panel often shows a clear error message explaining the problem — look for file name issues, path length errors, or sign-in prompts.
-
Check the file name of any flagged files. Remove or replace special characters such as # % & * : < > ? / | and leading or trailing spaces. Rename the file and the sync should resume.
SharePoint has stricter file naming rules than Windows. A file that saves fine locally may be rejected by SharePoint if it contains unsupported characters.
-
Restart the OneDrive sync client. Right-click the OneDrive icon in the taskbar → select 'Close OneDrive'. Then reopen OneDrive from the Start menu.
A temporary connection error or authentication glitch is often cleared by restarting OneDrive. This is a quick fix worth trying before anything else.
-
Sign out and sign back in to OneDrive. Right-click the OneDrive icon → Settings → Account → Unlink this PC. Then sign in again with your Microsoft 365 account.
If OneDrive's authentication token has expired (common after password changes), this is the fix. Your files are safe — unlinking does not delete them from SharePoint.
-
Resolve sync conflicts. If a file shows a 'conflict' error, OneDrive created two versions — one with your changes and one from the server. Open both, keep the correct version, and delete the duplicate.
Conflict files are named with 'computer name' appended. Open the OneDrive folder in File Explorer to find and resolve them.
When to Call a Professional
Most SharePoint sync errors are fixable by the user without IT support. If your organization's SharePoint site is consistently unavailable, contact your IT department. For issues affecting your entire organization's sync, an IT administrator needs to investigate server-side settings.
Frequently Asked Questions
Why does SharePoint sync work on one computer but not another?
Each computer runs its own OneDrive sync client with separate authentication. The computer where sync fails may have a stale sign-in, a path too long for that machine's configuration, or an older OneDrive version. Update OneDrive on the affected machine and sign out then back in to reset the sync.
What does 'file path too long' mean in SharePoint sync errors?
SharePoint limits the total length of the file path (folder structure + file name) to 400 characters. If your folder hierarchy is deeply nested and the file name is long, the combined path can exceed this limit. Move the file to a shorter folder path or shorten the file name to resolve it.
Are my files safe when SharePoint sync fails?
Yes. Files that failed to sync still exist in both locations — on your computer and on SharePoint (at the last successfully synced version). Sync errors do not delete files. Once you fix the error and sync resumes, both copies update to the latest version.