syncing problem.

If OneDrive shows Up to date but only some files are missing on other devices, check these causes first:

1. Hidden or temporary files in the OneDrive folder
   • Hidden and temporary files can show a syncing status in File Explorer but are not actually synced by OneDrive.
   • In File Explorer, enable hidden items and look for hidden files or folders in the affected OneDrive location.
   • Remove hidden files and folders that are not associated with files currently being edited.
   • Check for temporary Office files. Close open Office files, then clear the Office document cache. If temporary Office files still remain, only delete them if they can be safely removed.
   • Warning: deleting temporary Office files can cause data loss if the document is still needed.
2. Files that are stuck as hidden sync-pending items
   • If no visible file appears to be causing the issue, the problem may be a hidden file.
   • In File Explorer, go to View and enable Hidden items.
   • If no hidden file is found in the affected folder, create a new folder, copy the files from the affected folder into it, and then delete the original sync-pending folder.
3. Windows Search index showing an incorrect cached sync state
   • This can make files or folders appear to be syncing incorrectly even when OneDrive reports Up to date.
   • To test this:
     1. Open Services from Start.
     2. Open Windows Search.
     3. Set Startup type to Disabled.
     4. In Service status, select Stop, then select OK.
     5. Refresh File Explorer.
   • If the OneDrive folder no longer shows incorrect syncing status after the refresh, the cached search index was the cause.
   • Then revert Windows Search to Automatic (Delayed Start) and rebuild the index:
     1. Open Indexing Options from Start.
     2. Select Advanced > Rebuild.
   • Rebuilding the index can take time and is best done outside active hours.
4. Sync conflicts
   • A file can remain out of sync because of a conflict between the local and server copy.
   • For Office files, opening the file can start the conflict resolution experience.
   • Available actions can include Save a Copy or Discard.
   • For non-Office files, OneDrive can keep both versions, with the local copy renamed to include the device name.
5. Stop and reestablish the sync connection for the affected folder
   • In the Windows notification area, right-click the OneDrive icon and select Stop syncing a folder...
   • Select the affected folder and confirm Stop syncing.
   • This disconnects the folder from its library but keeps the files on the computer.
   • When syncing is started again, OneDrive creates a new synced folder. If the same name is used, a number may be added to the folder name.

A practical order is:

• Check hidden files and temporary Office files first.
• Then test whether File Explorer is showing a stale Windows Search index state.
• Then check for file conflicts.
• If the issue remains, stop and reestablish syncing for the affected folder.

References:

• The OneDrive sync status icon incorrectly shows "syncing" in File Explorer
• OneDrive is stuck on "Sync pending"
• Resolve sync issues in OneDrive for work or school
• Repair sync connections in OneDrive for work or school