ERROR: "User 'Sid~ExchangeOrg\migrationuser~RCA~false' has gone over budget '346' times for compo (4235388)

Migration to Exchange 2010 is very slow or fails. The eventlog on the migration workstation displays this error:

Process Microsoft.Exchange.AddressBook.Service.exe (PID=1636).
User 'Sid~org\migrationuser~RCA~false' has gone over budget '346' times for component 'RCA' within a one minute period.
Info: 'Policy:QuestMigration, Parts:AD:345;'. Threshold value: '100'.

The throttling policy is not set up optimal. The Quest Notes Migrator for Exchange (NME) documentation suggests that a throttling policy is created for migration purposes that sets 'PowerShellMaxConcurrency' and 'RCAMaxConcurrency' to '$null'. However, this is not sufficient for optimal performance.

In addition to 'PowerShellMaxConcurrency' and 'RCAMaxConcurrency' the following attributes should be set to $null as well:

• RCAPercentTimeInAD
• RCAPercentTimeInCAS
• RCAPercentTimeInMailboxRPC

The PowerShell command could be as follows:

Set-Throttlingpolicy QuestMigration -RCAMaxConcurrency $null -RCAPercentTimeInAD $null -RCAPercentTimeInCAS $null -RCAPercentTimeInMailboxRPC $null