To install the LAME MP3 encoder for Audacity, download the appropriate setup file from Lame.Buanzo.org, and initiate the setup process by double-clicking the downloaded executable file. Once the setup process completes, you should be able to export audio files in MP3 format.
To download the LAME MP3 encoder, navigate to the Lame and FFmpeg for Windows section on Lame.Buanzo.org, and click on the link for the Windows or Mac OS X version. In case the setup file doesnﾒt work properly, download the necessary files by clicking on the link that leads to the zipped version of the encoder. Once you download the file, double-click it, and follow the instructions until the installation process completes. You can safely ignore the prompt regarding the lack of verification for the publisher because, as of May 2015, Audacity has to use the LAME MP3 encoder from external websites due to problems with software patents. After completing the setup process, export audio files in MP3 format within Audacity by clicking on File, clicking on Export Audio and selecting the MP3 option.
To prevent potential problems with installation, avoid changing the default installation directory that the setup process automatically uses, and remove older versions of the LAME encoder DLL files from the directory where Audacity has installed.