Microsoft released Exchange 2010 SP3 Rollup 1 back in May, and the patch contains a nasty bug that causes the Transport service to crash. This crash happens when you are using disclaimer Transport Rules in your environment. When the rule is processed by the Exchange 2010 Hub Transport server the Transport service crashes and logs Event 10001:
Basically this bug means that as long as you are using disclaimer rules with Exchange 2010 SP3 Rollup 1 users will not be able to send or receive email. The email that caused the service to crash is dumped into the Poison queue:
The best fix for the issue is to install the recently released Exchange 2010 SP3 Rollup 2, which resolves this bug. You may download it from here: http://www.microsoft.com/en-us/download/details.aspx?id=39835&WT.mc_id=rss_alldownloads_all
If you are not able to update your Hub Transport servers right away then you must disable the disclaimer Transport Rules as there is no other work around.