I've been testing out MSAS Hotfix #931 and some additional developer builds from Microsoft. Everything was going pretty smoothly until I restarted the Analysis Manager on my test server and the list of my Analysis Server and the "Register Server" option was missing.
My heart almost stopped… What the H#$@$ did I do!!!
Anyway… After a hour or some of googling, I found the solution.
It appears that the msmdsgn80.dll (AS manager add-in) found a way to become un-registered.
MSAS is always so much FUN!!!