How to repair a corrupted Excel spreadsheet
I store all my documentations in my Dropbox so I can get access to them at anytime from anywhere. But this morning I found that one of the excel sheet I have in the Dropbox corrupted. And because it’s in the Dropbox, the corrupted version was on every single device I have Dropbox installed. Ooops, even on the Dropbox web console, I wasn’t luck enough finding a revision that works.
Out of luck of restoring it from any backup, I ran through number of options trying to repair it and finally got it repaired without paying a penny to any service or software. If you are down the road having the same problem, here are the things that you can try.
The error message that prompted is something like this:
Excel cannot open the file because the file format or file extension is not valid. Verify that the file has not been corrupted and that the file extension matches the format of the file.
And as you can tell, it doesn’t make too much sense, since the file in question is an Excel file with the right extension name associated. The only possible reason why I couldn’t open it is because it was corrupted.
1. Always try to recover it from a backup or a previous working revision
Even though it means that you may lose some current data, you get the file back with the data that is accurate.
2. Use Open & Repair in Excel
Open Excel, find and select the corrupted Excel file, instead of clicking open, choose Open & Repair from the down arrow in the Open button.

You will have the choice of Repair and Extract Data in the next dialog box after you click Open and Repair.

Go with the Repair first as it recovers the most out of the corrupted file, then Extract Data if the Repair failed.
3. Upload the corrupt file to Google Docs
What it ended up fixing my corrupted Excel is Google Docs. Can you believe it? I actually tried Office Web App first but got the same error as Excel client. Then out of curious what Google Docs might do to my spreadsheet, I uploaded to it and was open it successfully. I then downloaded to replace the one that was corrupted in my Dropbox.

4. Use Macro to extract the data
If none of above worked and the data in the spreadsheet is more important than anything else, the Macro shown in this document might be able to help you out.
5. Last resource
Of course, there are commercial repairing software out there that could also be helpful if you are REALLY running out of the options. Simply doing a Google search will bring you a bunch of them. But then you will have to try your luck to pick one that has the most possibility to fix your file.
