Hello, I've been able to use boxcryptor easily for about 2 years, but now on 2 of the machines I use, I get the following error message, when trying to open encrypted files in Excel.
"excel cannot open the file because the file format or file extension is not valid"
Because the files are encrypted, I can't do the Excel "open and repair" function.
Please could anyone advise how to fix this problem?
Thank you
