failed to uninstall last Exchange 2013

If you have to uninstall the first and last Exchange 2013 server in your org and failed with following errors:

Error:Uninstall can't continue. Database Mailbox Database XXXXXXXXX1 : This mailbox database contains one or more mailboxes, mailbox plans, archive mailboxes, public folder mailboxes or arbitration mailboxes. To get a list of all mailboxes in this database, run the command Get-Mailbox -Database . To get a list of all mailbox plans in this database, run the command Get-MailboxPlan. To get a list of archive mailboxes in this database, run the command Get-Mailbox -Database -Archive. To get a list of all public folder mailboxes in this database, run the command Get-Mailbox -Database -PublicFolder. To get a list of all arbitration mailboxes in this database, run the command Get-Mailbox -Database -Arbitration. To disable a non-arbitration mailbox so that you can delete the mailbox database, run the command Disable-Mailbox . To disable an archive mailbox so you can delete the mailbox database, run the command Disable-Mailbox -Archive. To disable a public folder mailbox so that you can delete the mailbox database, run the command Disable-Mailbox -PublicFolder. Arbitration mailboxes should be moved to another server; to do this, run the command New-MoveRequest . If this is the last server in the organization, run the command Disable-Mailbox -Arbitration -DisableLastArbitrationMailboxAllowed to disable the arbitration mailbox.

This is because you have one of the following:

• Still have folders in your Public Folders
• Still have Mailboxes in your Mailbox Datbases
• Still have Mailbox Databses

Exchange 2013 uses a number of different types of mailboxes as seen below. Even if you have removed all of your users mailboxes you must still remove these mailboxes:

DISCOVERY MAILBOX
DiscoverySearchMailbox {D919BA05-46A6-415f-80AD-7E09334BB852}
MONITORING MAILBOXES
HealthMailbox62256620620346798029c55bfe0fcc5d
HealthMailboxb67c72c285f54c30bad37dd37eec361a
HealthMailbox721771958fa64a53aa78527c02caf55b
HealthMailbox995793b82c2c4a14b6173e54371179ec
HealthMailboxc8603cb9bb41442e8b402db42f93dc16
ARBITRATION MAILBOXES
SystemMailbox{1f05a927-c403-4250-9f07-c5e43605c1ac}
SystemMailbox{bb558c35-97f1-4cb9-8ff7-d53741dc928c}
SystemMailbox{e0dc1c29-89c3-4034-b678-e6c29d823ed9}
FederatedEmail.4c1f4d8b-8179-4148-93bf-00a95fa1e042
Migration.8f3e7716-2011-43e4-96b1-aba62d229136

These mailboxes must be removed before you can actually uninstall Exchange 2013  You can remove these mailboxes from the ECP however if you you may need to use the command below to allow you to remove the arbitration mailoxes, this command allows you to disable them

Get-Mailbox -Arbitration -Database <MailboxDatabase> | Disable-Mailbox -Arbitration -DisableLastArbitrationMailboxAllowed

Replacing the Mailboxdatabase information with your own. Once removed if you start to unistall Exchange 2013 the uninstallation should complete

and last

Get-mailbox  -Database <mailboxdatabase > |disable-mailbox

after that try to uninstall your Exchange 2013 server again.

Good Luck!