Hi All I'm facing an issue in creating new Database in my Exchange 2010 SP2 which is in co-existence mode with Exchange 2007. When I'm creating new DB it is ending with a warning and after that it is failing to mount the database. If I'm attaching offline address book with database, I will be able to mount the database. I have Windows 2008 DC & Windows 2003 R2 ADC at main site and 5 ADC at branch site. Exchange installed in two VMs at main site one holing HUB/CAS Roles and the other holding Mailbox Role. Hope somebody can guide me to find a solution for this issue. Thanks in advance: vivek. Below is the warning message I'm receiving while Database creation Summary: 2 item(s). 1 succeeded, 1 failed. Elapsed time: 00:00:08<o:p></o:p> New test Completed<o:p></o:p> Warning: An error occurred while trying to prepopulate newly created mailbox "/o=First Organization/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=SystemMailbox{5a603c8f-b2aa-4d09-bfa8-7dcd63c68103}" in database "test" on server "SALMBX". "/o=First Organization/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=SystemMailbox{5a603c8f-b2aa-4d09-bfa8-7dcd63c68103}" may not immediately be available for certain cmdlets and operations until it has replicated. If you need to run the cmdlet again, and you want more information about the error, please add the -Verbose parameter. Error: 0x8004010F.<o:p></o:p> Exchange Management Shell command completed: new-mailboxdatabase -Server 'SALMBX' -Name 'test' -EdbFilePath 'C:\Program Files\Microsoft\Exchange Server\V14\Mailbox\test\test.edb' -LogFolderPath 'C:\Program Files\Microsoft\Exchange Server\V14\Mailbox\test'<o:p></o:p> Elapsed Time: 00:00:04<o:p></o:p> Mount test Failed<o:p></o:p> Error: Couldn't mount the database that you specified. Specified database: test; Error code: An Active Manager operation failed. Error: Couldn't find the specified mailbox database with GUID '5a603c8f-b2aa-4d09-bfa8-7dcd63c68103'.. [Database: test, Server: SALMBX.mycompay.local].<o:p></o:p> An Active Manager operation failed. Error: Couldn't find the specified mailbox database with GUID '5a603c8f-b2aa-4d09-bfa8-7dcd63c68103'.. [Database: test, Server: SALMBX.mycompany.local]<o:p></o:p> Exchange Management Shell command attempted: mount-database -Identity 'test'<o:p></o:p> Elapsed Time: 00:00:04<o:p></o:p> Vivek