Hello,

The download type is determined by audible, not Firefox. Firefox is at the bottom, following what it was told.

According to another question, it may be an issue that crops up in the javascript on Firefox, as they may simply be renamed to an mp4, and are actually aax, If this is true, simply rename the file with the aax file extension.

Unfortunately the problem is with Firefox 94! I have been downloading books from Audible (US, UK & AU) for over twenty years, mainly with Firefox. It started acting up only after version 94 was released. When it happened the first time I contacted Audible & they suggested trying a different browser. I tried the 'Brave browser' and 'Safari'. Brave downloaded the book as an '.aa' file and Safari as an 'aax' file. Yesterday I tried 'Opera' and it also downloaded as an '.aax' file.

Yesterday I also tried on my PowerBook Mac using an older version (87) of Firefox and it started downloading it as an 'aax' file before I stopped it.

Also, when the first time it happened I did try changing the extension but iTunes would not allow me to import it.

Try to change the .mp4 file extension to .aax.

• https://www.reddit.com/r/audible/comments/qbpvgu/are_all_downloadable_audible_files_now_mp4_what/
• https://www.reddit.com/r/audible/comments/q89c61/bug_alert_and_possible_solutions_for_win10firefox/