Prior to performing any import procedure please export existing configuration and make a backup of the existing System Manager or a snapshot from VMware for safer side.
go to Avaya Aura System Manager \ Users \ User Management \ Manage Users \ More Actions- Import Users
1. Import user and set "Delete Subscriber on Unassign of Subscriber from User or on Delete User" to uncheck to ensure Messaging Box is not deleted.
****use XML or Excel file and set "delete Subscriber on Unassign of Subscriber from User or on Delete User" to false and import. Verify ""Delete Subscriber on Unassign of Subscriber from User or on Delete User" is unchecked prior to proceeding to step 2. Failure to successfully uncheck this box will result in mailbox being deleted in AAM.
2. Import an XML file for the desired user (s) with the messaging profile configuration deleted- must use the "Replace" procedure. This removes the message profile configuration and hence the Message Profile is unchecked.