m4a - audacity cannot open this type of file

I had a really old version of audacity running on my win7 pc that worked fine.
I had the glorious idea to upgrade, so to have recent versions on pc and mac.
LAME and FFmpeg are reinstalled as well.
Still audacity now insists that m4a is an advanced file format it can’t deal with and asks me to convert to wav or aiff.
Extremely inconvenient - any suggestions?
Please - thank you!

Please restart Audacity, then click on “Help > Show Log”, then copy and paste the contents into your reply.