i started a migration from Exchange 2003 to Exchage 2010 , and on installation for the Exchange 2010 server to my enivornment the setup failed for all roles with a "Service could not enterRunning State" error .
then i figured that i had to add the servers that i will install Exchange 2010 on to the AD Security group "Exchange Enterprise Servers". well everything worked fine afterwards.
now every while i go to check the AD directory group i found that the servers are removed "like every 12 hours or so"and i have to manualy add them again. "may be with every AD replication am not sure"
does any one has an explanation for this behavior ?