Question : Exchange 2010. Install Failed, now can't uninstall

I was attempting to transition our Exchange 2003 environment to a new server running Windows Server 2008 R2 x64. I installed Exchange 2010, but the mailbox role failed. I tried three times to get it right without success. (My Exchnage 2003 server is still working perfectly)

I came back to the problem the following day to find that windows had done updates at 3am in the monring and restarted. Half the Exchnage services wouldn't start and it wouldn't let me install the mailbox role. It mentioned that the role was partially installed and that I must remove it first.

It will not uninstall the mailbox role with the following error:

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Summary: 6 item(s). 1 succeeded, 1 failed.
Elapsed time: 00:00:01


Preparing Setup
Completed

Elapsed Time: 00:00:00


Mailbox Role
Failed

Error:
The following error was generated when "$error.Clear(); get-PublicFolderDatabase -server $RoleFqdnOrName | remove-PublicFolderDatabase -RemoveLastAllowed" was run: "Public folder database "Public Folder Database 0475270718" is the default public folder database for the following mailbox database(s):
Mailbox Database 1204311301
. Before deleting the public folder database, assign a new default public folder database to the mailbox database(s).".

Public folder database "Public Folder Database 0475270718" is the default public folder database for the following mailbox database(s):
Mailbox Database 1204311301
. Before deleting the public folder database, assign a new default public folder database to the mailbox database(s).

Elapsed Time: 00:00:00


Stopping Services
Cancelled




Remove Exchange Files
Cancelled




Restoring services
Cancelled




Finalizing Setup
Cancelled

Answer : Exchange 2010. Install Failed, now can't uninstall

well it seems your installation is badly messed up

open adsiedit.msc -> connect to the configuration partition

browse to services -> ms exchange -> org name -> administrative groups -> exchange admin group (xxxxX) -> databases

find the public folder database and the mailbox database that were create on exchange 2010 and delete them

DISCLAIMER: adsiedit.msc could mess your whole organization if used wrongly, I am not responsible for any damage you do to your environment