Can the behaviour where the MSA checks if the final PRV has been processed by the MTA before switch (4248260)

From version 8.4 of the product, by default the Mail Source Agent (MSA) will check whether the Mail Target Agent (MTA) has processed the final PRV file that was generated before attempting to switch the mailbox.  This behaviour is to help ensure that mailboxes are not switched before the MTA has had chance to process all the data into target, and also to prevent switching if the MTA has an issue.

Can this functionality be turned off?

Example informational messages in MSA (Mail Source Agent) log file:

1. Last PST was not sent yet: MSAApp::GetLastPSTSendFlag TraceMsg 1002 The LastPSTWasSend flag is 'False'.
2. Setting the flag: MSAApp::SetLastPSTSendFlag TraceMsg 1003 Setting LastPSTWasSend flag.
3. Verification if last PST was sent and mailbox is ready to start switching: MSAApp::GetLastPSTSendFlag TraceMsg 1002 The LastPSTWasSend flag is 'True'.
4. Switch is attempted but not allowed before last PST is processed by MTA on the target:
CMBMSwitcher::IsSwitchAllowNow TraceMsg 6203 Checking whether target store is ready to switch. 
CMBMSwitcher::IsSwitchAllowNow TraceMsg 6205 Target store is not ready to switch.

This functionality can be turned off by adding a new line "LastPSTAppliedSwitch=0" under the [Mail Source Agent] section of the config.ini file that is located in the \Mail Source Agent\ folder on the source Exchange server.

Alternatively, to apply this setting globally to all \Mail Source Agent\config.ini files:

1. From the Migration Manager console, under the Exchange Data tab, select Tools | Options.
2. Highlight the "Additional parameters for agents configuration files". 

If this is not available, you can make this visible by opening regedit and navigating to HKLM\SOFTWARE\Aelita\Migration Manager\CurrentVersion\Exchange Data\ and creating the following Value:

Name: ShowAdditionalParameters
Type: DWORD
Value: 1

If the console is on a 64-bit system then the registry would be HKLM\SOFTWARE\WOW6432Node\Aelita\Migration Manager\CurrentVersion\Exchange Data

3. Click "Add" and enter "LastPSTAppliedSwitch" with a value of 0.
-Under "Apply to", Select "Agent Configuration" and "Quest Mail Source Agent" and click OK.  This will update all Mail Source Agent config.ini files to reflect the change.