The Microsoft Exchange Replication service on an Exchange Server 2010 server may freeze if a heavy I/O workload occurs. However, Windows does not trigger a Stop error to restart the server when this issue occurs.
To resolve this issue, install the following update rollup:
2746164 Description of Update Rollup 6 for Exchange Server 2010 Service Pack 2
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.