SharePoint sync issues when opening from File Explorer

Check this may help:

1.    Enable Office file collaboration in OneDrive
o    Right-click the OneDrive cloud icon → Settings → Office tab.
o    Check “Use Office applications to sync Office files that I open”.
o    This ensures autosave and co-authoring work when opening from File Explorer.
2.    Check Files On-Demand
o    In OneDrive settings → Advanced → ensure Files On-Demand is enabled.
o    Files should show cloud icons in Explorer. If they are only local, autosave may not work.
3.    Update OneDrive and Office
o    Make sure users are on the latest OneDrive client (Windows 11 ships with it, but updates matter).
o    Update Office apps to the latest build, older builds often break autosave integration.
4.    Verify sync method
o    Ensure the SharePoint library is synced via the modern OneDrive client (OneDrive.exe), not the legacy Groove.exe.
o    If Groove.exe is in play, autosave and co-authoring may not work.
5.    Test with a fresh sync
o    Stop syncing the library, clear cached credentials, and re-sync from SharePoint Online.
o    Sometimes stale credentials or cached sync metadata cause Office to misidentify the file source.
6.    Check file path length and naming
o    Windows 11 enforces stricter path length rules. If the path exceeds 260 characters, autosave may fail.
o    Rename or shorten folder paths if necessary.