A .docx exported from Apple Pages (or Scrivener/another Mac app) won't open in Word — "can't be opened", "problems with the contents", or Word reports the file is damaged

What's actually wrong

Pages, Scrivener and other Mac writing apps generate .docx files with their own OOXML writers, and those writers occasionally emit XML that Microsoft Word rejects — typically after you email the export to a Windows user and they can't open it. The document itself is intact in the original app on the Mac, so if you (or the sender) still have the source file, re-exporting a different way solves it completely. Only when the export is the sole surviving copy does this become a real repair job.

Free fixes — try these first

1. Re-export as .doc instead of .docx: in Pages use File → Export To → Word, click Advanced Options and choose .doc (Word 1997-2004). Word opens these reliably (in Compatibility Mode — use File → Info → Convert afterwards). This workaround is repeatedly confirmed in forum threads.
2. Launder through LibreOffice: open the rejected .docx in LibreOffice Writer on either platform, then Save As a fresh .docx — LibreOffice reads the nonstandard XML and rewrites it in a form Word accepts.
3. Round-trip through Google Docs: upload the .docx to Google Drive, open with Google Docs, File → Download → Microsoft Word (.docx).
4. Simplify and re-export: back in Pages/Scrivener, remove or flatten unusual elements (equations, linked media, footnote-heavy sections mentioned in bug reports), then export again.
5. Word's Open and Repair: File → Open → select the file → arrow beside Open → Open and Repair.

If the free fixes fail

When the Mac original is gone — a client sent only the export, or the Pages/Scrivener project was deleted — the rejected .docx is all that's left; our analyzer normalizes its nonstandard XML so Word will open it, and the free diagnosis tells you upfront whether it's a quick format mislabel (fixed free) or structural repair, with a percent-recovered preview.