The drop down menu that allows conversion from ACC to MP3 is gone. Only option is to convert to ACC which is the format when purchased.
iTunes
The option (AAC, MP3 etc) that shows will be the format that you've selected for importing music - go into Edit > Preferences (iTunes > Preferences on a Mac) and select the General tab and click the 'Import Settings' button at the bottom of it and change the import format to MP3 : iTunes: How to convert a song to a different file format - Apple Support
The drop down menu that allows conversion from ACC to MP3 is gone. Only option is to convert to ACC which is the format when purchased.
