The Mailbox Replication Proxy (MRSProxy) service is installed on every Exchange 2010 Client Access server. MRSProxy helps to facilitate cross-forest move requests and runs on the remote forest’s Exchange 2010 Client Access server. However, by default, MRSProxy is disabled.

If we are going to do a Cross forest move mailbox Source Forest Exchange 2010 Client Access Server should have MRS proxy enabled to facilitate the Remote move.

If the Source Forest CAS servers are in a Cas Array.

All Client Access servers in the Network Load Balancing (NLB) array must have MRSProxy started.

Otherwise you will end up with an Error:


To Enable MRS Proxy:

Set-WebServicesVirtualDirectory -Identity "EWS (Default Web Site)" -MRSProxyEnabled $true


To Increase Time Out:

Browse to the below location

C:\Program FIles\Microsoft\Exchange Server\v14\ClientAccess\exchweb\ews


Open Web.Config Using Notepad.

Browse to the bottom or Find Mrsproxy , get to the Below Location.

By default It will be “00:01:00” where if you feel MRS proxy gets to a idle time out we can increase that 20:00:00 minutes maximum.


Take a Copy of the Web.config File , you can change to “00:20:00” minutes as below.


Save And Close it.

Do a IISreset in your command prompt.

Reference Link: