In one of life’s “chicken and egg” situations I recently encountered the issue of promoting a Windows Server 2003 64-bit R2 server to be a Domain Controller in an environment with only Windows Server 2003 32-bit (non-R2) servers as existing Domain Controllers.

DCPromo will tell you that the Forest has not been prepared for the version of Windows you are trying to promote (ie, R2).  This would normally not be a problem, the R2 media contains an adprep.exe to update the schema for R2 Domain Controllers.

Of course if you take your new 64-bit R2 disc 2 media and try to run adprep on the 64-bit server you will receive this error:

Makes sense, so of course you put the disc into your existing Domain Controller and run adprep again.

Thats right, you can’t use your 64-bit media to run adprep on a 32-bit Domain Controller.  This is where the chicken and egg scenario kicks in – how do you get your 64-bit R2 server to be a Domain Controller with no pre-existing 64-bit or R2 Domain Controllers available for the required schema update?  Its not like Microsoft ships you a 32-bit copy of the OS when you buy the 64-bit edition.

The solution is to get your hands on the 32-bit R2 media.  If you don’t have a friend or colleague with a copy the next easiest way to get it is from the trial software downloads on Microsoft.com.  Go here and jump through the ridiculous hoops to “buy” a $0.00 trial edition so that you can download the ISO files.  You only need to download and burn the ISO for disc 2 which contains the R2 adprep.exe and schema files.

Update: you can also download this hotfix that contains only the R2 adprep files.