Hi, when I first installed Audacity in winows 7, I remember that I also had to install the Lame software. I didn’t understand or understand why this was necessary, and I’m still wondering. I’ve since upgraded to Windows 10 and 11 and reinstalled and upgraded Audacity, but I still don’t understand what that Lame software does, and whether it’s still necessary.
LAME was needed to create/export mp3 files at the time when mp3 was still a copyright-protected format. After mp3 became “public” (don’t know what legal wording to use), it was built into Audacity. I think this was around version 3.2 or so of Audacity. Therefore, with recent Audacity-versions you no longer need to install LAME.
However, you should install the Audacity-specific version of ffmpeg to create/export some other file formats. Look into the Audacity manual for more information.
romontschun beat me to it…
It’s been built-in for many years and many versions so you no longer have to worry about it. 
LAME is used to make MP3 files. When you export as MP3 Audacity is using LAME. That’s all it does. It was never used to import/open MP3 files.
…In the old days, MP3 had a patent (which has expired) and you were supposed to pay a licensing fee and of course that’s impossible with open-source software. LAME was also open source but the user was supposed to compile it themselves for “educational purposes”. But I think the compiled files were hosted by someone who was willing to take the risk.
It’s still the case with FFmpeg which is used to import/export many other formats.
I know of one developer who was sued for including LAME in their application without paying licensing fees to the company that owned the MP patent. I never heard of them going-after an end user.
Ok, thank you both.