Error creating MAPI profile for mailbox in Unity backup

[K_require]

While taking disaster backup in Unity 4.0(5.0), we encountered the error as:

[11:05:55] Error creating MAPI profile (ExMerge - THN_EXCHANG(294cf389) - 18 Jul 08).(CMapiSession::CreateEMSPSTProfile)

[11:05:55] Errors encountered. Copy process aborted for mailbox 'THN_EXCHANGE_EV' ('THN_EXCHANGE_EV').

How to overcome this issue?

[mchin345]

Reason might be Sometimes when you add a user and that user is not able to log into the mailbox you need to recreate the user.