File Doctor — Repair & Recover Files
Drop a broken or "won't open" file and fix it in your browser: correct a wrong extension, trim junk bytes, rebuild a damaged ZIP/Office archive or PDF, and remux a media file that won't play. Nothing is uploaded — everything runs locally.
How to Use
- Drop the broken file in (or click to browse). Any file works — it's read locally, never uploaded.
- Read the diagnosis: what the file really is, and what's wrong with it.
- Click the suggested repair — fix the extension, trim junk, or rebuild the structure.
- Download the repaired file and try opening it again.
Drop a broken file or click to browse
Any file — it's read & repaired in your browser, never uploaded
A repair shop for broken files — in your browser
Drop in a file that won't open, downloaded wrong, or got flagged as "damaged," and File Doctor reads what it really is from its magic bytes, checks its structure top and bottom, and tells you plainly what's wrong. Then it offers the fix: correct a wrong or missing extension, trim junk bytes added before or after the real file, rebuild the index of a damaged ZIP or Office document, re-serialize a broken PDF, or remux a media file whose container won't play. Everything happens locally — the file is never uploaded — so it's safe for private documents and footage.
What it can and can't do
It can fix structure. A huge share of "corrupt" files aren't missing data at all — they have a wrong extension, a few stray bytes from a bad download, or a damaged table-of-contents while the real content is intact. Those are exactly what File Doctor rebuilds.
It can't invent data that was never written. If a transfer stopped halfway and the rest of the file simply doesn't exist, no tool can reconstruct it — and you should be wary of any site that claims otherwise (especially one that wants you to upload the file first). File Doctor is honest: when a file looks truncated, it says so, and recovers whatever is present rather than pretending.
Reference
About the File Doctor — Repair & Recover Files
The File Doctor — Repair & Recover Files gives you a fast, free answer for image, audio and file tasks without sending anything off your device. Drop a broken or "won't open" file and fix it in your browser: correct a wrong extension, trim junk bytes, rebuild a damaged ZIP/Office archive or PDF, and remux a media file that won't play. Nothing is uploaded — everything runs locally.
How it works
Type in what you have, and the answer shows up right away. Change anything and it updates by itself. Everything runs in your browser, so it is fast and nothing you type is sent away.
Want the deeper story? The Knowledge Base explains the ideas behind the tools in more detail.
Frequently Asked Questions
Is my file uploaded anywhere?
No. "Drop a file to fix" means it\'s loaded into your browser\'s memory and repaired with local code — it never leaves your device, and nothing is stored. That\'s important for files you can\'t risk sending to a stranger\'s server.
What can it actually fix?
Structural and container damage: a wrong or missing file extension, junk bytes added before or after the real file, a damaged ZIP / Office (docx/xlsx/pptx) archive index, a broken PDF cross-reference table, and media files that won\'t play because the container is malformed (a remux usually fixes those).
What can't it fix?
It can\'t bring back data that is genuinely gone. If a download stopped halfway and the second half of the file was never written, or bytes were overwritten with zeros, no tool — local or online — can reconstruct the missing content. File Doctor will tell you honestly when a file looks truncated rather than pretend it fixed it.
My file opens but looks wrong / has a weird extension.
Drop it in — File Doctor reads the real format from the file\'s magic bytes, so it catches things like a “.jpg” that is actually a PNG, or a file with no extension at all, and offers to rename it correctly.
How is this different from File Inspector?
File Inspector reads and analyses a file in depth (formats, metadata, forensics). File Doctor is the repair shop: it focuses on finding what\'s wrong and producing a fixed copy you can download.
How do I use the File Doctor — Repair & Recover Files?
Just type your numbers. The answer shows up right away — there is no button to press. Change anything and it updates by itself.
Does it cost anything or need an account?
No. The tool is completely free, there is no account to create, and it keeps working offline after the page first loads.
Is anything I type uploaded?
No. The tool works entirely on your device, so the values you enter never leave your browser.
Common Use Cases
Won't-open download
A file that downloaded with junk or a wrong extension and won't open.
Corrupt ZIP / Office file
Rebuild the index of a damaged .zip, .docx, .xlsx or .pptx.
"Damaged" PDF
Rebuild a broken PDF cross-reference table so it opens again.
Video that won't play
Remux a malformed MP4/MKV container so players accept it.
Mystery / no-extension file
Identify the real format and give it the correct extension.
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