Currently Backup Exec does not support backing up and restoring Exchange running in Multi-Tenant Mode.
There are three ways to determine if Exchange is running in Multi-Tenant mode:
1) Since all activity within Multi-Tenant mode is performed via Exchange Powershell; there will be no Exchange console installed on the Exchange server.
2) There will be a new Organizational unit created with Active Directory called "Microsoft Exchange Hosted Organizations" (See image)
3) Three new security Groups are created under Microsoft Exchange Security Groups: (See image)
a) Management Forest Monitoring
b) Management Forest Operator
c) Management Forest Tier 1 Support