I am running Microsoft Office 2017 (15.34) on a MAC desktop. I just upgraded to Ios Catalina.

Although I was told my version of Office would work "fine", I have problems with ExCel. For whatever reason, files ending in ".xlsx" are unreadable (eg., some data is reversed or upside down, etc.). My main file has over 100,000 rows. I have had to divide it into two separate files and save as ".xls".

Is there a fix or would Office 2019 work well with Catalina?

Thanks in advance