Environment
Retain 2.5 or higher
Exchange 2010
Situation
Resolution
The error indicates that either you have a throttling policy applied or the Exchange server is busy. Microsoft Exchange 2010 uses client throttling policies by default to track bandwidth for each Microsoft Exchange user and enforce bandwidth limits as necessary. Throttling policies should be turned off for the Retain Service Account, because they can affect the performance of Retain for Exchange when accessing mailboxes with a large number of folders and mail items.
1. On a computer that hosts the Microsoft Exchange Management Shell, open the Microsoft Exchange Management Shell.
Type: Get-ThrottlingPolicy
This is the default Throttling Policy.
2. Type these commands:
a. New-ThrottlingPolicy [give it a policy name of your choosing] -RCAMaxConcurrency $null -RCAPercentTimeInAD $null -RCAPercentTimeInCAS $null -RCAPercentTimeInMailboxRPC $null -EWSMaxConcurrency $null -EWSPercentTimeInAD $null -EWSPercentTimeInCAS $null -EWSPercentTimeInMailboxRPC $null -EWSMaxSubscriptions $null -EWSFastSearchTimeoutInSeconds $null -EWSFindCountLimit $null
b. Set-Mailbox [Retain impersonation user account] -ThrottlingPolicy [policy name from step "a"]
3. Check the Throttling Policy for the "retain" impersonation user.
Get-ThrottlingPolicy -Identity [policy name from step "a"] | Format-List
Which should return something like this: