Today I updated my Audacity from version 2.1.1 to version 2.4.2, after that I can’t import long MP3 files (between 1 hour and 1,5 hours) from my MAC folders. I imported the same file on 2.1.1 version succesfully.
During the importation process, after few seconds I got these error message: Lost syncronization and the process stops.
I also tried to import smaller files from ITunes without any problem.
Steve answered this in a thread on the Linux board. I’ll just quote him here …
There was previously a problem with Audacity incorrectly identifying some file types. To fix this problem, Audacity’s MP3 importer had its error checking enabled. Unfortunately it was discovered after the release of 2.4.2 that there are a lot of MP3s that do not comply with the MP3 standard, and with error checking enabled Audacity rejects these files.
For the next Audacity release, error checking of MP3s has been toned down so that non-critical errors will again be ignored and MP3s will successfully load unless they are critically damaged.
One workaround (until the next release of Audacity is available), is to use the “file type” dropdown menu in the “Import Audio” dialog and select “FFmpeg compatible files” before selecting the MP3 file to import. (see: https://manual.audacityteam.org/man/importing_audio.html#filetypes) That should allow you to import MP3s that do not strictly comply with the MP3 standard.