How to Disable Hold Music in Cisco Unified Call Manager

log into Cisco Call Manager Administration
Click  Service
Click Media Resouce
Click Music On Hold Server
Select a MOH server
Change the run flag to "No."

This will unregister the Music On Hold server. The Status will show "Not Registered"
Instead of hold music, users on hold will hear "Tone on Hold", three short beeps every 5 or 6 seconds.