What kind of sound file are you using? TB won't accept any format, and standard wav files work best.

As stated in my original report, it is a "mp3" file which originally played fine. Another thing, it will not allow me to change what is entered in the browse window!

An mp3 won't work unless you add a wav header, a step that requires a basic audio editor. Or, decode the mp3 to a wav file.

OK, assuming I can decode the .mp3 file to a .wav file, being as the program will not allow me to change what is in the browse window, how do I get the new file in the window?

I've no idea why the Browse button doesn't work for you, as it works fine here on W10/TB 91.

The Browse.. button worked fine when I entered the current .mp3 file. Just that now I can't delete that file or enter another file into the window.

Open Config. editor in Preferences/General/Indexing, copy mail.biff.play_sound.url into the search, click the reset icon (left-pointing arrow) to remove the current mp3.

OK - I was able to remove the .mp3 file and after converting the worfmail.mp3 to worfmail.wav and saving it to my hard drive, I again used the Browse button to locate the file (C:\ThinkPad\WAV Files\worfmail.wav) and here is what was pasted into the window file:///C;/ThinkPad/WAV%20File/worfmail.wav. I sent myself an e-mail and the tune did not play. What the heck (being nice) am I doing wrong?

I just did a test with the worfmail.wav file found here. Sent myself a message and the sound played. Don't paste the path into the box, use Browse and select the file.

OK - I think it is working now. I think that the .wav copy I was trying to use was corrupted. It would play using VLC Media Player but not with Windows Media Player. I downloaded a new copy, saved it and placed it in the window and it now works. It is strange that the .mp3 version used to work in Thunderbird. Oh well, it works now so that is all that matters. Thanks a bunch for all of your time and effort. It is greatly appreciated. - Hal