We have recently migrated to SCCM 2012 from our previous 2007 install and have already uninstalled 2007. The problem is that our WSUS server has both the 2007 and the 2012 clients in it's database and is trying to install both of them to client computers. Is there a way to remove or expire the 2007 client from WSUS without reinstalling WSUS?
I was able to fix this issue using Greg Ramsey's blog post. Basically I took his powershell script and replaced the GUID with the one I found in the file system directory that contained the 2007 ccmsetup.exe in it.
It is important to note that the script has to be run on the WSUS server.