Suddenly - no import, export MP3

Greetings. I have been using Audacity ever since it came out. I have used it every day - maybe 15 years, and extensively. Today I am in the middle of some important edits and all of a sudden, no importing of MP3s! I tried and tried, re-installing, downloading FFMPEG, Lame, etc. Went through whatever I could find on the internet. Now I find myself with a deadline and can get no farther. I don’t know what else I can tell you. Windows 10. The error is like "Audacity did not recognize this type of file. Try installing FFmpeg. Weird! Any suggestions? I’m using 2.4. I was thinking there was a later version. Look - this program has been my mainstay for all these years. I am flabbergasted that it is no longer working today! Thank you,

Is that 2.4.0, 2.4.1 or 2.4.2?
Did you recently update Audacity?

Can you make one of MP3 files available for us to test (preferably a small one), for example via dropbox or Google Drive?