'Unable to open target mail store' occurs for different migrated accounts each time the migration runs (4317758)

'Unable to open target mail store' occurs for different migrated accounts each time the migration runs

When migrating a large user collection with Migrator for Notes to Exchange (MNE), the migration starts out successful and after a large number of migrations are performed MNE is no longer able to contact the target Exchange mailbox.  

Note: When migrating the same User collection again different accounts will fail with the following error:

17:04:50 ERROR: [4965-24-55-8004010F]Unable to open target mail store

This is caused by configuring Outlook to use the same profile rather than prompting for credentials to access mailboxes in Exchange.

Close MNE and Microsoft Outlook prior to performing these steps.

1. Open the Windows Server Control Panel and click on Mail (32bit).
2. Under 'When starting Microsoft Outlook, use this profile:' ensure the radio button selected is 'Prompt for profile to be used.'
3. Click OK and start the migration again.