I was able to successfully record two cassettes, exported as MP3 files. Since then it has not worked. Now the recording seems to be working. An MP3 file is created, but the file size is 0. I had this problem with version 1.2.6. I’ve downloaded version 2.0, and I have the same problem. Does anyone have any suggestions. I’ve given up!
Check in “Edit > Preferences > Libraries”.
Which version of Lame is installed?
It’s version 3.99.3.
Could you try these steps as a basic fuctionality test:
- Open Audacity (if it is already open, close Audacity and then relaunch it)
- From the Generate menu, select “Tone” and generate a tone.
- From the File menu select “Export” and export the tone as an MP3 file.
- From the File menu select “Import > Audio” and import the file that you have just exported.
You should now see a duplicate copy of the original “tone” track.
Does that work?
I can hear the tone. I just wasn’t playing it earlier. However, I still cannot record tapes as MP3 files.
Is there anything else I should try?

I still cannot record tapes as MP3 files.
For clarity, Audacity does not “record as MP3”.
Audacity creates “Audacity Projects”.
From the Audacity project you can then “Export” an MP3.
Please read this section for more detail, this is a crucial concept: http://manual.audacityteam.org/man/Audacity_Projects

Is there anything else I should try?
Yes.
Try recording something and then press the “Play” button.
Does it play?
If it does, Export as “WAV (Microsoft) 16 bit PCM”.
Find that exported file and try to play it. Does that work?
If it does, go back to the (already open) Audacity project, check that it still plays, and export as MP3.
Does that work? If not, where did it go wrong?