Data Merge - import files greyed out
Hi All,
I'm trying to perform a data merge on a business card design but when I go to choose the data file it's greyed out. It was working earlier today but now it's not - even with the same files.

I have created a new blank .indd file and various new data files with very limited basic data, using a wide variety of .csv and .txt formats and saving in both Excel and TextEdit, but none of my data files are recognised for import. If I choose to show all documents rather than just readable, and select any file I get this error message.

Mac has been rebooted several times.
Having Googled extensively I can't find any mention of this issue 😞
TIA, Mandy
MacBookPro - Big Sur - InDesign 16.1 - Excel for Mac 16.16.2
