Mutes on D-Show master section don't work.
 

Our '08-vintage D-Show ( with latest software ) has shown up with an intermittent muting issue. Sometimes the mutes on the output fader section on the main control surface work; other times they don't. The problem generally toggles after a power cycle, but it's a crapshoot as to whether this will happen on any particular cycle. The mutes always work on-screen, or in response to an implicit mute; the buttons on the control surface surface are the issue.

Re: Mutes on D-Show master section don't work.
 

Given the age, you might want to flip the panel over and take a look at the contacts. They might just need a good cleaning.