How to Repair a Corrupted Excel File That Will Not Open

Few things cause as much anxiety as an Excel message saying it “found unreadable content” or that “the file is corrupt and cannot be opened”. Especially when that file holds weeks of work, the quarter’s accounts or the only copy of a customer list. Before you give up on it, it is worth knowing that most corrupted files can be fully or partly recovered. In this guide you will see why files get corrupted and which steps to follow, from simplest to most complex.

Why Excel files get corrupted

The most frequent causes are:

• Unexpected shutdown: a power cut, a computer freeze or closing Excel while it was saving.
• Storage problems: disk errors, USB drives removed without ejecting or cloud sync failures.
• Incomplete downloads or attachments: the file was not fully downloaded.
• Failed conversions: an external program produced a file with an incorrect structure.
• Very large or complex files: workbooks with huge numbers of formulas, formats or external links.
• Viruses or malware, less common but possible.

First of all: make a copy

Copy the corrupted file to another folder before trying to repair it. Some repair attempts can make things worse, and you will always want to keep the file exactly as it was so you can try another method.

Step 1: use Excel’s Open and Repair

Excel includes a repair feature:

1. Open Excel (without opening the file).
2. Go to File > Open > Browse.
3. Select the corrupted file.
4. Click the arrow next to the Open button and choose Open and Repair.
5. Click Repair. If that does not work, repeat and choose Extract Data, which recovers values and formulas even if formatting is lost.

Excel will show a report of what it was able to repair or remove.

Step 2: restore a previous version

If the file was stored in OneDrive, SharePoint, Google Drive or Dropbox, there is very likely a version history. Right-click the file on the service’s website and look for “Version history”. Restore the last version that worked.

On Windows, if File History or restore points are enabled, right-click the file and choose Properties > Previous Versions.

Step 3: look for AutoRecover files

If Excel closed unexpectedly, reopening it should show the Document Recovery pane. If it does not appear, go to File > Info > Manage Workbook > Recover Unsaved Workbooks. Excel saves automatic copies every few minutes depending on your AutoRecover settings.

Step 4: open the file with another program

LibreOffice Calc and Google Sheets use different reading engines and sometimes open files that Excel rejects. If you manage to open it, immediately save it as a new XLSX file.

Step 5: use an online repair tool

Repair tools analyze the file’s internal structure, rebuild the damaged parts and extract all the data that is still readable. With the spreadsheet repair tool on our Excel tools page, which supports XLS, XLSX and CSV files:

1. Upload the corrupted file.
2. The tool tries to rebuild the workbook.
3. Download the repaired file and review its contents.

It is especially useful when Excel offers no options or the built-in repair removes too much content.

Step 6: extract the data manually (XLSX)

An XLSX file is really a ZIP. If everything else fails and you are comfortable with technical steps:

1. Change the extension from .xlsx to .zip.
2. Open the ZIP and go into the xl/worksheets folder.
3. The files sheet1.xml, sheet2.xml and so on hold each sheet’s data; text values are in xl/sharedStrings.xml.

It is laborious, but it lets you rescue data from badly damaged files.

After recovering

Once you have a file that opens:

• Compare it with an earlier version using our Excel comparison tool to check which data was recovered and what is missing.
• Review formulas and links, which may have turned into values or broken.
• Save it under a new name in XLSX format.

How to prevent corruption in the future

1. Turn on AutoRecover every 5 minutes in File > Options > Save.
2. Work in synced folders with version history.
3. Do not open files directly from USB drives; copy them to your disk first.
4. Use XLSX instead of XLS: it is more resilient to partial damage.
5. Split huge workbooks into several smaller files.
6. Reduce the size of heavy files with an Excel compressor.
7. Back up important files regularly.

Frequently asked questions

Conclusion

A corrupted Excel file is not always a lost file. Start with Excel’s built-in repair, look for earlier versions and AutoRecover files, try other programs and turn to an online repair tool if nothing works. Above all, adopt prevention habits so you do not have to go through it again. Find the repair tool and other free utilities on our Excel tools page.