Excel cannot open the file 'XXXX.xlsx' because the file format or file extension is not valid.

[zguzman1795]

I am a MAC user

I AGAIN encountered an error opening my excel file after the excel update AUG 15 2023. Error says "

Excel cannot open the file 'budget 9.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."

I have experienced this 2x after excel updates.

This is an important file and I don't know how to recover. This happened last July and now Aug, after the release of update in Excel.

@Pernille-Eskebo @microsoft @Deleted @microsoft @Excel 

[#2]

@zguzman1795 

Do you have the option of opening the file anyway? That is, is the message you're getting a warning, or is it saying you absolutely cannot open the file?

I ask because I get the following from one particular file (which I download from a reputable financial services firm), and it is just a warning; I'm still able to open it, but I'm obviously assuming responsibility for doing so.

Your message asks you to "verify that the file has not been corrupted" which seems similar, although the rest of the message is definitely more ominous.

And what did you do last July? Did you end up having to re-create the file?

[#3]

@mathetes i am definitely unable to open it. No option to open