How do I fix a corrupted XLSX file?

Try Excel's built-in repair: File → Open → Browse → select file → click arrow next to Open → choose 'Open and Repair'. If that fails, try opening in Google Sheets, rename to .zip and extract content, or use specialized recovery tools.

Can I recover data from a corrupted Excel file?

Often yes. Excel's Open and Repair function works for many cases. You can also try Google Sheets (sometimes opens corrupted files), extracting raw XML data from the XLSX (which is a ZIP file), or using tools like Stellar Repair for Excel.

Fix: "Excel Cannot Open the File"

Q: Why does Excel say the file format is not valid?

This error occurs when Excel can't recognize the file structure. Common causes include: file is corrupted, wrong extension (file isn't actually XLSX), file is too old (Excel 95 format), or the file was damaged during download or transfer.

Solutions for file format not valid, corrupted spreadsheets, and extension errors

⚡ Quick Fix

Open and Repair: File → Open → Browse → select file → dropdown arrow → "Open and Repair"
Check extension: File might be .xls (old format) or .csv renamed to .xlsx
Try Google Sheets: Upload to Google Sheets — often opens corrupted files
Re-download: Get fresh copy if from email/internet

Learn more: See our complete guide on how to open XLSX files on any device.

The "Excel cannot open the file because the file format or file extension is not valid" error is frustrating but usually fixable. The file may be corrupted, mislabeled, or in an older format.

Why Excel Can't Open Your File

Corrupted file — File damaged during save, transfer, or download
Wrong extension — File is CSV, XLS, or other format renamed to .xlsx
Version mismatch — Created in newer Excel than yours can read
Incomplete download — File didn't download fully
Protected workbook — Encrypted or protected from opening
Storage corruption — Damaged on hard drive or cloud sync issue

Solution 1: Use Excel's Open and Repair

Success rate: 55% — Built-in recovery tool

Open Microsoft Excel (don't double-click the file)
Go to File → Open → Browse
Navigate to your XLSX file
Click the file once to select it
Click the small arrow next to "Open" button
Select "Open and Repair"
Choose "Repair" first; if that fails, try "Extract Data"

"Extract Data" option: If Repair fails, Extract Data can recover cell values and formulas, though formatting may be lost.

Solution 2: Check the Real File Format

Success rate: 40% — Common with downloaded files

The file might not actually be XLSX:

Verify file type:

Right-click the file → Properties
Look at "Type of file"
If it doesn't say "Microsoft Excel Worksheet", the extension is wrong

Common mismatches:

.xls (Excel 97-2003) — Rename from .xlsx to .xls
.csv (comma-separated) — Rename to .csv and open with Excel
.xlsm (macro-enabled) — Rename to .xlsm
.xlsb (binary) — Rename to .xlsb

Solution 3: Open in Google Sheets

Success rate: 50% — Different parser may succeed

Go to Google Sheets
Click the folder icon → Upload
Upload your XLSX file
If it opens, download as new XLSX (File → Download → Microsoft Excel)

Solution 4: Extract Data from XLSX ZIP

Success rate: 35% — Manual recovery method

XLSX files are actually ZIP archives containing XML files:

Make a copy of your XLSX file
Rename copy from file.xlsx to file.zip
Extract the ZIP (right-click → Extract All)
Navigate to xl/worksheets/
Open sheet1.xml in Notepad or browser
Look for your data between <v> tags

Note: This recovers raw cell values. Formulas, formatting, and charts won't be preserved.

Solution 5: Update Microsoft Office

Success rate: 25% — Fixes version compatibility

Open any Office app
Go to File → Account
Click "Update Options" → "Update Now"
Wait for updates to install
Restart Office and try opening file again

Solution 6: Disable Protected View

Success rate: 30% — For files from internet/email

Open Excel → File → Options
Go to Trust Center → Trust Center Settings
Click "Protected View"
Temporarily uncheck all three Protected View options
Click OK and try opening the file
Re-enable Protected View after (security best practice)

Solution 7: Try LibreOffice Calc

Success rate: 40% — Free alternative

Download LibreOffice
Open LibreOffice Calc
Try opening your XLSX file
If it opens, save as new XLSX

Frequently Asked Questions

Why does Excel say the file format is not valid? +

Excel can't recognize the file's internal structure. The file may be corrupted, have the wrong extension (not actually XLSX format), be too old for your Excel version, or was damaged during download or email transmission.

How do I fix a corrupted Excel file? +

Use Excel's built-in repair: File → Open → Browse → select file → click dropdown arrow next to Open → choose "Open and Repair". If that fails, try Google Sheets, LibreOffice, or the ZIP extraction method.

Can I recover data from a corrupted XLSX? +

Usually yes. Excel's "Extract Data" option in Open and Repair can recover values. Google Sheets often opens partially corrupted files. For severe corruption, XLSX files are ZIP archives — you can extract and manually recover the XML data inside.

Why does the same file open on another computer? +

Different Office versions handle files differently. The other computer may have newer Excel, different security settings, or the file was re-downloaded without corruption. Try updating your Office or adjusting Protected View settings.