How to Disable Throttling in Microsoft Exchange Server 2010

Microsoft Exchange Server 2010 message throttling policies set bandwidth limits and restrict the number of processed messages. In order to disable throttling, you must create an appropriate policy and assign it to the service account as documented in the Microsoft TechNet article Set Throttling Policy.

Step 1. Create Service Account

If you have not already done so, create a new service account using the steps in the article Creating an Email Service Account for Microsoft Exchange Server. Otherwise, proceed to Step 2: Assign Permissions.

Step 2. Assign Permissions

Use the following steps to assign the Microsoft Exchange Server service account to the Application Impersonation Management role:

1. Log in to the Exchange Server as the administrator.
2. From the Start menu, go to Start > Programs > Microsoft Exchange Server 2010 > Exchange Management Shell.
3. At the command prompt, type the following command replacing serviceAccount with the account created in Step 1: Create Service Account:
   New-ManagementRoleAssignment -Name:exchangeImpersonation -Role:ApplicationImpersonation -User:serviceAccount

Step 3. Create and Assign Throttling Policy

Use the following steps to create and assign a new throttling policy, replacing PolicyName  with the new policy name, and replacing PolicyAdmin with the Exchange Server 2010 service account created in Step 1: Create Service Account:

1. Log in to the Exchange Server as the administrator.
2. From the Start menu, go to Start > Programs > Microsoft Exchange Server 2010 > Exchange Management Shell.
3. At the command prompt, type the following command:
   New-ThrottlingPolicy PolicyName
4. Press Enter. At the command prompt, type the following command:
   Set-ThrottlingPolicy PolicyName -RCAMaxConcurrency $null -RCAPercentTimeInAD $null -RCAPercentTimeInCAS $null -RCAPercentTimeInMailboxRPC $null -EWSMaxConcurrency $null -EWSPercentTimeInAD $null -EWSPercentTimeInCAS $null -EWSPercentTimeInMailboxRPC $null -EWSMaxSubscriptions $null -EWSFastSearchTimeoutInSeconds $null -EWSFindCountLimit $null
5. Press Enter. At the command prompt, type the following command:
   Set-Mailbox "PolicyAdmin" -ThrottlingPolicy PolicyName
6. Press Enter.