Your file won’t open.
The words are usually still inside.
When Word says “unreadable content” or a download dies half-way, it’s normally the file’s index that broke — not your writing. Mendery reads the raw bytes and pulls out everything that survived, right here in your browser. Nothing is uploaded, ever.
No broken file at hand?
- Provably private A strict Content-Security-Policy forbids this page from sending data anywhere. Open DevTools → Network while you use it: nothing leaves. (If you see Cloudflare’s own injected scripts being blocked in the console — that’s this policy working.)
- Free & open source MIT-licensed, ~1,500 lines you can read. No account, no “premium tier”, no watermarks held to ransom.
- Works offline Once loaded, it keeps working with the network cable pulled. Save the page (⌘S / Ctrl+S) and keep a copy.
What it can — and can’t — recover
Usually recoverable
- Files whose ZIP index broke — Word/Excel/PowerPoint show errors, but the content streams survived intact.
- Truncated files (interrupted save, download or sync): everything up to the cut, often most of the document.
- Text, tables, headings and lists from .docx and .odt; cell values from .xlsx; slide text from .pptx; rows from SQLite databases — including from destroyed database headers.
- Embedded images, when their bytes survived.
- A rebuilt .docx that opens in Word again, when the main text stream was recovered.
Honestly not recoverable
- Files replaced with zeros by a failed sync or disk error — the content is simply not in the file anymore. The guide below is your real path.
- Bytes inside the damaged region itself. Mendery recovers around damage; it cannot re-create what was destroyed.
- Encrypted or password-protected documents.
- Exact layout, fonts and formulas — content first, cosmetics second.
If Mendery can’t recover it either
Don’t give up — the best copies of your document usually live outside the broken file. Work down this list:
- Cloud version history. OneDrive: right-click the file → Version history (official guide). Google Drive: right-click → Manage versions (official guide). Versions are typically kept about 30 days.
- Word / Excel / PowerPoint AutoRecover. On Windows: File → Info → Manage Document → Recover Unsaved Documents (Microsoft’s guide). On a Mac, AutoRecovery files live in each app’s container — Finder → Go → Go to Folder (Microsoft’s Mac guide).
- Word’s own repair. File → Open → select the file → arrow next to Open → Open and Repair (Microsoft’s guide). It fixes different damage than Mendery does — worth trying both.
- LibreOffice backups, if you use it: Tools → Options → Load/Save → General shows whether backup copies are on, and where they go (official help).
- Email & chat trails. The version you sent your supervisor / colleague / yourself last week is a real backup. Search your Sent folder.
How it works
Modern Office documents (.docx, .xlsx, .pptx, .odt) are ZIP archives. A ZIP keeps its table of contents — the central directory — at the very end of the file, which is exactly where truncation and interrupted writes hit. When that index dies, Word and every normal unzip tool declare the whole file unreadable, even though the actual content streams sit untouched a few bytes away.
Mendery ignores the index. It scans every byte for the local signatures that precede each inner file (PK\x03\x04), decompresses whatever survives — keeping the partial output when a stream dies mid-way — and turns the recovered XML back into readable text with a parser that tolerates truncation. If enough survived, it re-packages your text as a fresh, valid .docx. SQLite databases get the same treatment at the page level: every 4KB page is read independently, so one destroyed region only costs the rows that physically lived there.
Standing on shoulders: the salvage technique descends from zip -FF, BruteZip and Paul D. Pruitt’s file-repair freeware, and closed-source in-browser ZIP repair exists (ezyZip, MyFileFixer). Mendery is an independent implementation; what it adds is the open combination — MIT source anyone can audit or fork, a privacy promise enforced by the browser (CSP), truncation-tolerant structured preview, honest damage reporting with real fallback routes, and (as far as we could find) the first fully in-browser recovery of corrupted SQLite databases.