When attempting a original mailbox or a redirected restoration to an Exchange 2010 mailbox containing  characters in the display name, such as Test User [OR] or Test User [TX], the restore will fail.
0xe00002fc - Cannot restore one or more mailboxes. The database that the mailboxes reside in is dismounted or is not accessible. Ensure that the server is available and that the database is mounted, and then run the job again.
A hotfix is now available for this issue in the current version(s) of the product(s) mentioned in this article. Refer to the Hotfix link under Related Documents at the end of this article to obtain the hotfix needed to resolve the issue.
Backup Exec 2012 Rev 1798 Service Pack 4 (TECH212772).
Option 1: Re-direct the GRT restore to a mailbox that does not contain  characters.
Option 2: If Backup Exec 2012 is used, re-direct the GRT restore to PST, then import the necessary mail data via Outlook.
This issue occurs during Exchange 2010 GRT restores to mailboxes with the a display name that contains  characters, such as Test User [OR]. The issue does not affect Exchange 2003 or 2007 configurations.