I already have exchange 2003 Server running in my organization, I decided to setup Exchange 2007 to interoperate at the same time with the 2003. During the Exchange 2007 installation, it detected that the 2003 exchange server is present which I selected. Installation was successful but then I decided against moving the already existing 2003 mailboxes to 2007, so what did I do? I created two new mail-enabled users in 2003 and move them over to 2007 but what I found out is that they can only send mails to each other but will not send to any mail enabled 2003 users. After much frustration, I decided I want to uninstall my exchange 2007 since I actually set it up for lab purpose but it wont uninstall. Each time I start the un-installation process I get this errors: Summary: 4 item(s). 0 succeeded, 4 failed. Elapsed time: 00:02:40 Unified Messaging Role Prerequisites Failed Error: Setup cannot use domain controller 'v-dc.mydomain.com' because an override is set in the registry. Run Setup again, and specify '/DomainController:'. Elapsed Time: 00:02:30 Client Access Role Prerequisites Failed Error: Setup cannot use domain controller 'v-dc.mydomain.com' because an override is set in the registry. Run Setup again, and specify '/DomainController:'. Elapsed Time: 00:00:02 Hub Transport Role Prerequisites Failed Error: Setup cannot use domain controller 'v-dc.mydomain.com' because an override is set in the registry. Run Setup again, and specify '/DomainController:'. Warning: There are 3 messages waiting in the 'v-mail\Unreachable' queue. Proceeding with the removal of the server role may result in data loss. Elapsed Time: 00:00:03 Mailbox Role Prerequisites Failed Error: Setup cannot use domain controller 'v-dc.mydomain.com' because an override is set in the registry. Run Setup again, and specify '/DomainController:'. Error: Uninstall cannot continue. Database 'Public Folder Database': The public folder database that you specified is in use by a mailbox database. Mailbox database: Mailbox Database. Recommended Action: http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.3&id=b6e3b32a-8848-46cb-9567-72288ac15f60 Elapsed Time: 00:00:02 If I try to run uninstall in the power shell I get this error: the is a version mismatch between the running application and the installed application Hints: v-dc.mydomain.com is the FQDN of my the machine acting as my DC V-mail is the name of the Exchange 2007 server Any suggestion will be highly appreciated. Regards, jummy

Hi, jummy. Don't know, whether you've resolved your problem already, but the solution should be: Rename the following registry entry at your exchange server: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchange ADAccess\Instance0 For example, rename "Instance0" to "XInstance0". That's, what I've found at another location, and it worked! Regards, Ronald

Hello Ronald, It worked! it worked!!, but where have you been all this while. You just help to solve a 2months nightmare less than 10mins. I am really grateful. Thanks alot. If you don't mind canyou send your e-mail address to my mailbox: fathersheart2k@hotmail.com , i still have some problems on E2k7 i will like to share with you. Once again, thanks. Jummy

Hi Ronald, After making this changes and succesfully uninstall E2K7, i revertedthe changes back to Instance0. i have monitored my event logs to see if this will log in any error but so far, no error message or anything unsual has been noticed. I have also extended the monitoring to the E2K3 server, but all is fine also. I only wanted to be sure if ican use ADSIEDIT.MSC to remove the container forthe Exchange Administrative Group (FYDIBOHF23SPDLT) in the ESM of the E2K3 server, or it will it be okay to just right click and delete. What do you think? Do you also think reverting the changes back to instance0 will have any effect on my network? Hope to get a reply from you soon. Regards, Jummy

Hi Jummy, very glad to see that my hint was helpful. I'm really not an expert concerning exchange server, because I set it up as a test system without upgrading from another product to see, whether it's suitable as a production system. Then I recognized the same problem and searched the net for 2 days, finding the solution I provided to you. Therefore, I cannot give you any statement regarding AD-entries from E2K3 server :-( Nevertheless I do not guess, that the "instance0"-entry has ANY effect on your network, because it's a local entry specifically for exchange. I even didn't revert the entry to assure the correct access of the AD! Regards, Ronald

Hello Ronald, No prob, i have already removed theentries frrom the E2k3 server using ADSIEDIT.MSC and so far, there has been nothing unusual. Also reverting the changes to the "instance0" has no effect on my network. So far, all is well. Once again, thanksfor your time. Regards, Jummy