The file format and extension of 'file.xlsx' don't match
Excel showed "The file format and extension of 'file.xlsx' don't match" because the filename and the bytes did not identify the same workbook format. FileFix can test whether damaged .xlsx package content remains and summarize any validated rebuild. A one-time $14 — and only if the repair works.
Free preview — pay only if you download ($14)
Your files auto-delete — delete them sooner anytime
No person looks at your file as part of repair
Uploading your file.
Keep this tab open while the file transfers. Large files can take a few minutes.
Starting upload...
Recovering what we can.
Analyzing your file...
Here's what we recovered.
Review the recovery summary before checkout.
Your files auto-delete — delete them sooner anytime
No person looks at your file as part of repair
Repair your file
Choose a supported file to see what can be repaired before checkout.
Simulated checkout — no payment is processed.
Optional — we'll email your private download link.
You preview before you pay. If the download is materially worse than the preview you approved, we'll refund you.
Try another fileGood news — your file isn't damaged. No charge.
There's nothing to repair. If it still looks broken, the issue may be the player, codec, or viewer on your device rather than the file itself.
We couldn't recover this one.
The file is too damaged to rebuild, so there is nothing to preview and no charge.
Have another clip from the same device?
A healthy video recorded on the same device — ideally the same settings — gives the repair engine a template to rebuild from. It can unlock repairs that fail on their own.
Unrepaired files are kept encrypted for up to 30 days, then deleted.
FileFix can't fix that kind of file yet.
Right now we repair video, audio, document, and image files (MP4, MOV, M4V, MKV, AVI, TS, MTS, M2TS, MPG, MPEG, VOB, 3GP, WebM, FLV, M4A, WAV, MP3, AAC, FLAC, OGG, AIFF, XLSX, DOCX, PPTX, ODT, ZIP, PDF, AI, HEIC, and HEIF). We're adding support for more formats over time.
Something went wrong.
The request could not be completed.
Try repairing your file
FileFix can often repair this kind of damage if the file is recoverable.
Why this happens
This warning is an identity check. It appears when a file named .xlsx contains another format, or when damage to the ZIP package prevents Excel from recognizing the workbook structure the extension promises.
Renaming a file does not convert its contents. If the upload contains recoverable Excel package members, they can be placed into a fresh .xlsx; unrelated bytes cannot be turned into the expected workbook.
FileFix scans for workbook members, rebuilds recoverable worksheet and shared-string XML, and reports the validated sheets, rows, and masked sample from the output.
What we can and can't recover
We can usually fix
- Files that show "Excel found unreadable content"
- Files Excel calls an invalid format or extension
- Workbooks cut off mid-save or mid-transfer
- Files that show the right size but won't open
We can't fix
- Password-protected/encrypted workbooks
- Genuinely empty (0-byte) files
- Deleted or formatted files (that's data recovery, a different job)
- The old binary .xls format (this repair is for .xlsx)
How it works
-
Upload Drop the file in. It uploads over an encrypted connection. The repair runs automatically — no person looks at your file.
-
Free Recovery Summary You see exactly what we recovered — sheet names, row counts, and a small sample.
-
Pay & Download If the summary shows what you need, unlock the repaired Excel file for a one-time $14.
You see a recovery summary built from your actual file before you decide anything — so you never guess.
See what's recoverable.
Free recovery summary · private & auto-deleted
Browse by problem
Questions
Not by itself. The message means part of the workbook package failed Excel's checks — the rest is often intact. What is actually recoverable only becomes visible when a rebuild is attempted, which is what the free sheet-and-row summary shows you.
Try it on a copy and review the repair log Excel produces. Save any result under a new name and confirm your important sheets survived; if the recovery drops what you needed, upload the untouched file for a separate rebuild.
The removal happened in the copy Excel saved, not in your original file. If you still have the untouched .xlsx, upload that one — a separate rebuild works from everything still inside the package, not from what Excel chose to keep.
Excel discards package parts it cannot parse rather than repairing them. A different engine may recover some of those parts, which is why the FileFix summary reports what its own rebuilt workbook contains.
Working from the original untouched .xlsx gives the engine the most to recover. If Excel has already saved a stripped-down version, keep the original copy and upload that instead.