SharePoint library won’t sync: causes and fixes

The problem

SharePoint libraries sync to your PC through the OneDrive app, so they share OneDrive’s rules and add a few of their own. Library settings, permissions and required metadata can stop a library from syncing, or make it sync as read-only.

Symptoms

• The Sync button is missing from the library toolbar in the browser.
• A message says the administrator does not allow the library to be synced.
• The synced library opens as read-only, so changes cannot be saved back.
• Some files sync while others show errors or never appear.
• Copies of files appear with a computer name added to the file name.

Causes

• Offline availability is turned off

  A site or library owner can prevent syncing. The Sync button then disappears or sync is refused.

• Check-out or required columns

  Libraries that require check-out, or have required columns or validation, sync as read-only.

• Wrong or expired credentials

  The OneDrive app must be signed in with the account that has access to the library, usually your Microsoft 365 account.

• Conflicts

  When local and server copies differ, Office files show a conflict to resolve. For other file types, OneDrive keeps both and adds your computer name to the local copy.

• Names, paths and sizes

  Unsupported characters, paths over 400 characters and files over 250 GB do not sync.

• Unsupported sync locations

  A network or mapped drive cannot be used as a OneDrive sync location.

How to fix it

1. Confirm you can open the library in a browser

   Sign in to Microsoft 365 and open the library. If you cannot access it, ask the site owner for permission before troubleshooting sync.

2. Check whether the library allows syncing

   Site owners: open Site settings, then Search and offline availability, and set Offline Client Availability to Yes. Library owners: open Library settings, then Advanced settings, and set Offline Client Availability to Yes.

3. Check for read-only conditions

   In Library settings, review whether check-out is required and which columns are required. These settings keep the library read-only in File Explorer.

4. Sign in with the right account

   Open OneDrive settings and confirm the work or school account matches the one you use for SharePoint.

5. Resolve conflicts

   Open conflicting Office files to resolve them in the app. For other files, compare the two versions, keep the right one and delete or rename the other.

6. Fix names and long paths

   Rename items with unsupported characters and shorten paths that exceed the limits. See the guides on invalid file names and path length.

7. Stop syncing and sync the library again

   If many errors remain, stop syncing the library from OneDrive settings and sync it again for fresh data. Your files stay in both places when you stop syncing.

When OneDriveSyncFixer helps

Microsoft documentation

• Fix SharePoint Online sync problems (opens in a new tab)support.microsoft.com
• Resolve sync issues in OneDrive for work or school (opens in a new tab)learn.microsoft.com
• Restrictions and limitations in OneDrive and SharePoint (opens in a new tab)support.microsoft.com

This guide summarizes Microsoft’s published guidance in our own words. Microsoft documentation remains the authoritative source.