Thanks for the post. Did you try/verify everything in the error message?

there is a known issue with RVTools latest version causing a malformed xlsx file; which is what the last bullet point in the error message fixes. If not, something else may be going on…

I checked for all the items in the list specified.  Same error.  The rvtools version used was 4.5.1.15.  I tried different browsers as well.

Hi ​@Eddie.P did you meanwhile resolve this? I have tested new/unmodified versions from 4.4.1-4.7.1.4 without issue. Perhaps try a newer version (4.6->). Ensure the file hasn’t been modified (rows added, summarizations/formulae/etc). If still no luck, I’d be curious to dig a bit deeper with you.