Starting EmailXtender exEmail.exe service brings server to it knees

try removing and readding the connection mailboxes in email administrator. don't forget to activate changes.

Greetings,

Data Source Service (ExEmail.exe) is one of the binaries that does most of the work on EX. I usually keep Data Source service as the last service to be started because it can chew CPU upto 99% and also it does a lot of other things before it starts to pull down mail from journaling mailboxes. I have realized one fact that if you have descent size MSGCENTER then data source starts quickly than usual. Having number of connection mailboxes also adds up.

As suggested by the user above try removing and adding back connection mailbox, I would go one step further by adding one connection mailbox at a time if you have multiple mailboxes to be added as connection mailboxes.

Hope this helps.

Thanks,
Raj