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How to Remove First or Default Exchange 2010 Database

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I have seen several questions from EE users where they are unable to delete the default database created during Exchange server installation. I have answered the same question several times. I thought of writing an article, which can help EE users.

Below, I explain the steps of how to delete the first database. Let us check what we need to do before dismounting and removing the first database.

First step is to move or remove following type of mailboxes from first database:

1) Any user mailbox
2) Any Archive mailbox
3) Discovery Search mailbox
4) Arbitration mailbox

If you forget to move or remove mailboxes you will get the below error:

The mailbox database "Default DB" cannot be deleted.

Note: I am using Default DB as DB name in this article for First Database. It could be different in your case.

So let’s start moving all of the above mailbox types to another db.

1) Move User Mailboxes:
For these types of mailboxes we can use Exchange Management GUI Console or PS. I prefer EMC as it is easy to use. First login to your Exchange server, launch EMC. Browse to EMC>Recipient Configuration>Mailbox

Create a filter Database>Equal>DBName and Apply filter. This will show you all user mailboxes stored on your first database. Select all mailboxes, right click and click on New Local Move Request and move all mailboxes to another database by following the New Local Move Request wizard.

2) Move Discovery Search Mailbox:
Steps are same as above. It will be named like DiscoverySearchMailbox???

3) Move Archive Mailboxes:
In case you have created any Archive Mailbox on first database. Make sure to move them as well to another database. You can do this with user mailbox move step also.

4) Move Arbitration mailbox:
This one step, where I have seen maximum people struggle to complete and post question on EE site regularly. First these mailboxes are not visible using EMC and can be found using EMS or Exchange management Shell only.

Before, I explain you the steps. First understand these mailboxes are stored at Forest level. So make sure to run this command first.

Set-AdServerSettings -ViewEntireForest $True

Next run below command to view Arbitration mailbox stored on your first database.

Get-Mailbox -Arbitration -Database “Default DB"

Next run below command to move Arbitration mailboxes to another Database.

Get-mailbox –arbitration –database "default db" | new-MoveRequest –targetdatabase "Target DB"

To view the move status run below command

Get-MoveRequest -Sourcedatabase "Default DB"
Get-MoveRequest -Targetdatabase "Target DB"
Open EMC>Recipient Configuration>Move Request

Once all mailboxes are moved and move request shows as completed 100%, you can clear the all move requests and then you can dismount/remove the database.

For dismounting and removing DB. Goto EMC>Organization Configuration>Mailbox>Database Management

Select the first database>Right Click Dismount then Right click again and Select Remove.

Finally, browse to db path in your machine and delete the edb and logs files.

I hope this article will help everyone. Please let me know your comments or suggestions.

Expert Comment

Amitkulshretha, you are a genius! I think the one command that solved my issue was

Set-AdServerSettings -ViewEntireForest $True

Before I ran that command, all the other commands either did nothing or told me the systemmailbox could not be found. That Set command broke the log jam.

Thanks so much!!!!

Expert Comment

$AdminSessionADSettings.ViewEntireForest = $True  

(Modify the Scope To Forest)

Expert Comment

I moved arbitration mb to another db and I was able to delete default DB
Get-mailbox –arbitration –database "default db" | new-MoveRequest –targetdatabase "Target DB"

however when I ran
 Get MailboxDatabase |ft  
i do see 3 of my current DB listed as well as two previously deleted  database which don't have any mailbox or even a folder.
how do I remove phantom DB names ?
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Expert Comment

I know this may be root, but should i backup before the move and specifically what?
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Author Comment

I request you to post a question with details and send me the link via message.

Expert Comment

I am going to have to move all of the mailboxes from one database in Exchange 2016 to an existing database that has existing mailboxes resident. When I list the databases I see some common mailboxes in both databases. The database I want to move the mailboxes from will be deleted and recreated. Do i move these common mailboxes as well? Please see below

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