A CSGO sound engine change was rolled out on 2018-04-30. As a result of this, various ZE maps have lost mapmusic.

To fix it, place text below in your CSGO startup config:
snd_disable_legacy_audio_cache "0"

For example in:
C:\Program Files (x86)\Steam\steamapps\common\Counter-Strike Global Offensive\csgo\cfg\autoexec.cfg

If you are not already using autoexec, then you need to create the file and add the launch option.

Steam Libray > Right-click CSGO > Properties > SET LAUNCH OPTIONS > add: +exec autoexec > press OK

Quit CSGO and re-open CSGO for fix to work.
« Last Edit: May 05, 2018, 01:40:31 PM by Satō »
Example autoexec config:

// Fix for missing ZE mapmusic sound
snd_disable_legacy_audio_cache "0"

// Confirm
echo +++ autoexec.cfg executed successfully +++

// Write to configs.cfg
« Last Edit: May 05, 2018, 01:40:57 PM by Satō »
"snd_disable_legacy_audio_cache" command has been deleted in the 2018-05-04 CSGO update.


"Fixed an issue where MP3’s embedded in maps wouldn’t work. (Thanks to Steam user MajesticCatDog for help in diagnosing this issue)."

^ Hopefully the above update fix works.