Solved The file format/file extension is not valid.

December 25, 2014 at 07:38:33
Specs: Windows 7
I am using MS Office 2007 on my pc and I have several excel files which I always use at work. Naturally I used these files daily until recently. Yesterday I have faced an error while I tried to open my working files on Excel: Excel cannot open the file .xlsx 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.
How can I fix this error?

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December 25, 2014 at 07:47:29
Some possible bad news, see here:

If above is not your problem then try here:


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December 27, 2014 at 02:30:00
✔ Best Answer
First try to rename file. Go to tools, folder options, file types and check have you .xlsx extension. If not then rename the file .xlsx to .xls

Second try to use excel command in file menu – Open and Repair. File, open, select the corrupted file and click open and repair option.

Another recommended solution: if you was unable to resolve this problem through above steps then you should try any third-party software. There are a lot of them on the internet, both free or pay versions.

Also you can find more information here:

And good luck!

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