Ok, there have been times over the years, where due to one reasons or another you may have had to completely remove your Exchange installation from your domain and then re-install it (hopefully not too often in production, but perhaps a couple of times in test).

Today I had to rip my Test Exchange lab apart and completely remove the Exchange organisation and re-install. The removal went well (really, it didn’t complain) however the problems arose when I tried to run Exchange setup again.

Firstly it claimed that I needed to run “forestprep” again, which when done failed with an error message which claimed that I needed to run Forestprep and also needed to be in the Exchange Administrators group, or be using an account that has delegated permissions on the Exchange Organisation.

Odd I thought - there is now no Exchange organisation (as I removed it) and technically forest prep has been run, so why does setup now have a problem with me running Exchange setup.

Ironically, the solution to this problem came to me quite quickly – I fired up ADSI edit and had a look under the Domain and Configuration Partitions I found the following Entries still in place;

Domain;

CN=Microsoft Exchange System Objects

Configuration;

CN=Microsoft Exchange,CN=Services

I deleted these entries and then ran setup.exe / forestprep and the installation proceeded “tickity boo”