Did you look at " Microsoft Exchange 2010 on VMware
Best Practices Guide
Have you look at the system logs?
Have you look at the vcenter perfromance logs?
Pay close attention to msftefd.exe proces the store.exe procerss
O.k - I checked all the logs in the exchange and in the event viewer - NOTHING
i also test the server with Best Practice Analyzer and also NOTHING.
I invited a VMware expert and he did some changes in the ESXi like resource allocation and priority - but still NOTHING.
The solution is totally REMOVING the antivirus (ESET Nod32) from the server!!!!!!!!!
can you recommend about new better antivirus that made specially for exchange servers ?