Exchange 2010 Database and Mailbox Removal

Hi Everyone

I'm having a mailbox issue with Exchange 2010.

About a week back i decided to create 3 more databases on Exchange server (to speed up recovery time in case of crash).

I then proceeded to run local move request and devide the mailboxes up equally between the 3 databases.

All request completed successfully.

I now want to remove the old database from the server.

First ran the following command to see all existing mailboxes in the database.

Get-MailboxStatistics -Database “Mailbox Database" | Where-Object {$_.DisconnectDate -Notlike $NULL} | FL DisplayName, DisconnectDate, MailboxGuid

This provided me with a full list of mailboxes left.

I then proceeded to run the remove mailbox command in powershell to remove the mailboxes one at a time.

Remove-Mailbox -Database “Mailbox Database " -StoreMailboxIdentity 4de027ac-748d-4d6d-b2fc-da8f25ab4bce

But instead of asking me to remove the mailbox i get the following error

Mailbox "4de027ac-748d-4d6d-b2fc-da8f25ab4bce" doesn't exist on database "Mailbox Database".
    + CategoryInfo          : NotSpecified: (0:Int32) [Remove-Mailbox], ManagementObjectNotFoundException
    + FullyQualifiedErrorId : B2E5E082,Microsoft.Exchange.Management.RecipientTasks.RemoveMailbox

Any help would be appreciated.