The SQL Server 2012 Upgrade Advisor has a poorly undocumented prerequisite. If you go and try and install the Upgrade Advisor off of the SQL Server 2012 RTM media, you will get the following error:
The installer is looking for the SQL Server 2012 Transact-SQL ScriptDom component which is found as part of the SQL Server 2012 Feature Pack.
You can find them here for x86 and here for x64.
After you install the ScriptDom package, you will be able to install the Upgrade Advisor.
I complained about this privately to Microsoft in December (it did the same thing in RC0). Nobody replied to my message.
Agreed -it really makes no sense why they couldn’t put the code on the DVD – it’s only a few megabytes.
Well I think it’s so that they can release updates in an easier way, but let’s be honest, most of the time when I have to download something like this, I throw it on a network share or external drive, even if it is tiny.