Hi EM
When I export to Save as XLSX, it saves and everything looks fine.
When I try import it into another program, it says there is a file format issue - and I see “.xml” test strings are being picked up within the files first few rows.
When I open that file (in Excel), and resave it in the exact same sport, everything works fine.
Also note that this system had been working for over a year before it through up the error - about a month ago from what I can see.
Rob