I lost my audio alerts as well with version2.15.2.  I tried everything in the book; Windows audio settings, JTAlert settings, program start/restart, etc....but no dice.
Finally gave up and reverted to version2.15.1 and everything works fine.  I saw another post where someone used a software to reload his previous
Windows settings but does not specify what values changed (for those of us who do not utilize that software).  I have had no problems in the life of JTAlert
when upgrading so this has me baffled. I assume that the reversion indicates a changed Windows setting.  Hopefully someone will be able to identify the problem
so we can get back to upgrading.
Also, a heartfelt thanks to all those involved in the development of this fun software.
Mike N8FRI