A document stored in OneDrive or SharePoint suddenly won't open after syncing — Office reports unreadable content or "the file is corrupt and cannot be opened", even though it worked yesterday
Any Office file · what this error means and every free fix to try first
A document stored in OneDrive or SharePoint suddenly won't open after syncing — Office reports unreadable content or "the file is corrupt and cannot be opened", even though it worked yesterday
What's actually wrong
When Office saves a file, it writes a new copy and swaps it in — if the OneDrive or SharePoint sync client uploads mid-swap, or the connection drops during upload, one side ends up with a half-written file. Usually only ONE copy (local or cloud) is actually damaged, and OneDrive silently keeps previous versions of every file. That means this situation is almost always recoverable without any repair tool — the real skill is knowing where the healthy copy lives.
Free fixes — try these first
- Restore a previous version. Go to onedrive.com (or the SharePoint library) in a browser, right-click the file → Version history, and open versions from before the corruption. Restore the newest one that opens cleanly. This works in the vast majority of sync-corruption cases.
- Compare the cloud copy with the local copy. Download the file directly from onedrive.com (Download button, not the sync folder) and try it. Then try the copy in your local OneDrive folder. Sync corruption usually damages only one of the two.
- Open and Repair. In Word/Excel/PowerPoint: File → Open → Browse, select the file, click the arrow next to Open → Open and Repair.
- Roll back your whole OneDrive. Microsoft 365 subscribers: onedrive.com → Settings → Restore your OneDrive lets you rewind everything up to 30 days — useful if many files got corrupted in one sync event.
- Reset the sync client so it stops re-corrupting on re-download: press Win+R, run
%localappdata%\Microsoft\OneDrive\onedrive.exe /reset, then let it fully re-sync before opening files.
If the free fixes fail
If the corruption synced before you noticed and every version in the history is already damaged, version restore can't help — our analyzer then reads the raw file structure and shows you exactly what percentage of your text, sheets, or slides is still intact before you decide anything.
Check what's recoverable — free, in your browser.
Drop the file on our analyzer. It runs locally (the file never leaves your computer) and shows you an honest recovery percentage with a real preview. If nothing is recoverable, we say so plainly — and you pay nothing, ever, for the diagnosis.
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