opsdog
This odd behaviour is described elsewhere in this MC22 forum at "MediaCenter won't load anymore on my Mac
« on: August 06, 2016, 06:21:23 pm »" by AlexW. The thread shows how you can start the program from terminal but not the dock. It only arises on 10.8.5 as far as I can see.
I also had the problem in MC21 whereby I could install up to 21.0.77 from new but later builds could only be upgraded from within MC when running. Later builds gave the familiar bouncing icon on a fresh install with no result. Later I found that I could not install any MC22 builds on 10.8.5 either and that was a big problem.
In the MC21 thread, the gurus here suggested it was a known bug in OS 10.8.5, particularly build (12F2560), this naturally being the last upgrade from Apple to normal update users.
I took their advice and moved on to a more recent Mac OS and have had no trouble since. It seemed crazy updating an OS for one app but if you are on the point of upgrading anyway, this may well push you over the edge.
http://yabb.jriver.com/interact/Smileys/classic/undecided.gifGood luck tracking down the root cause
Mike