MP3-saving disappeared after an update. What happened?
You may need to update your LAME encoder framework if you're using an older version of Sound Studio.
Delete all previous versions of the LAME encoder. The LAME framework files are in the Library/Frameworks directories. Go to Finder > Go > Computer > Macintosh HD > Library > Frameworks. Then, delete the LAME.framework file(s). Then, download and install the LAME encoder.