Word experienced an error trying to open the file.

What's actually wrong

This message usually does NOT mean your document is corrupted. In most cases Windows has flagged the file as coming from the internet (email attachment, school portal, download) and Word's Protected View refuses to render it, or the file sits in a location Word doesn't trust. Only a minority of cases are genuine structural damage — so try the security fixes first, because they recover the file completely with zero data loss.

Free fixes — try these first

1. Unblock the file: right-click the .docx in File Explorer → Properties → General tab → tick Unblock (bottom right, next to Security) → OK. Reopen it. This alone fixes the majority of cases with downloaded or emailed files.
2. Move it out of the risky location: copy the file from Downloads, a network share, or a synced folder to your Desktop or Documents, then open the copy. If it opens, the original location was the problem, not the file.
3. Temporarily relax Protected View: in Word go to File → Options → Trust Center → Trust Center Settings → Protected View, untick the three boxes, restart Word and try again. If it opens, save a local copy, then re-enable Protected View — it protects you from malicious documents.
4. Open and Repair: in Word, File → Open → Browse → select the file → click the arrow on the Open button → Open and Repair.
5. Try a more tolerant program: open the file in LibreOffice Writer (free) or upload it to Google Docs. If either reads it, re-save/download as a fresh .docx and Word will accept it.

If the free fixes fail

If the file still errors after unblocking and Open and Repair, the container itself is damaged (truncated download, broken ZIP structure) — our analyzer inspects the actual bytes, tells you for free whether it's real corruption or just a mislabeled format (mislabels are fixed free), and shows an honest percent-recovered preview before you commit to anything.