Hello,
Is there any previous version available under "Previous Versions" tab?
May I know the status of this file from sync center?
Do the file on both server and client side all show 18kb? If they are different, right-click on the sync group and choose "View sync conflicts" (or similar) to find and resolve any conflicts.
Or check if there is backup solution for the network drives, which could contain the latest version of your file.
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