Hi,
dear friends, I am also going through the same situation with Zentyal 4.2 installed on an HP ML110 host, in this case there is no problem of the link with virtualized environment.
Just a CPU crash, leaving the slow service and even compromising all other Zentyal services, to the point of halting the OS and have to restart.
Informardo was that just reinstalling the Samba service fixes the problem, or has otherwise?