The Exchange Server User Monitor (ExMon) RPC data indicates that client restrictions are causing high load on this server. ...

The Exchange Server User Monitor (ExMon) RPC data indicates that client restrictions are causing high load on this server. Restrictions account for {0}% of the processor usage devoted to processing RPC requests. This is expected for a short while after a large number of mailbox moves. Investigate if you have not moved mailboxes recently.