Installation error when upgrading Exchange 2010 to SP1

I encountered a strange issue when I upgraded an Exchange 2010 installation just the other day. I could not find any technet articles or other blog posts with anything similar to my error. So I thought I'd share my error and solution.

The installation is a rather small one, so I have all the roles co-located on one server.

First of all, I was not able to upgrade using GUI at all. It told me I had to select components, even though all the components were already selected. It just gave me a nonsense error message. It was only after disabling the UMserver (as suggested by this document: I was able to run the wizard.

Unfortunately I was still not able to install the service pack from the GUI. I then tried to run the /m:upgrade /installwindowsfeature from command prompt. The setup still feiled. When studying the error setup logs (great logging of the setup by the way) I noticed it was complaining about not being able to read the language-packages. And this is where I was puzzeled: The setup was looking for the languagepack on the desktop of my administrator account, not in the setupdirectory I was running setup from.

My simple solution to the problem was this: Copy all the language folders to the desktop. I rebooted the Exchange server (A failed install will need to be rebooted before running setup again) and ran again. And this time it worked just fine.

Anyone with a good explanation on the placements of the language files? Please drop me a note in the comments section ;)