Recently I had a run-time heap corruption problem in our software which is caused by some internal changes in the beta CLR and .NET Framework assemblies. This software uses lots of interop code, it become broken because of these changes in the fw.
So, I decided to uninstall the beta frameworks from my machine but it’s happened to be not such a trivial thing to do. I asked Aaron Stebner in Microsoft for some help who responded me kindly and promptly. Thanks for it. :)

Here is his answer:

“The original version of the .NET Framework 3.5 included the .NET Framework 2.0 SP1 and 3.0 SP1, but it created separate Add/Remove Programs entries for 2.0 SP1 and 3.0 SP1 so you could uninstall all of the pieces as long as you uninstalled in the exact order of 3.5, 3.0 SP1, 2.0 SP1. That same behavior should be the case for 3.5 SP1 as well.

One thing that might be different here – on Windows Vista and Windows Server 2008, the .NET Framework 2.0 and 3.0 are OS components, so they will not show up in Add/Remove Programs. If you are running one of these OS’s, you will need to use steps like this to remove the .NET Framework 2.0 SP2 and 3.0 SP2:

1. Uninstall the .NET Framework 3.5 SP1 product from the Programs and Features control panel
2. In the Programs and Features control panel, click the link on the left named View Installed Updates
3. In the list of installed updates, look for an item named Update for Microsoft Windows (KB948609) – this is the .NET Framework 3.0 SP2
4. Right-click on the item and choose Uninstall
5. In the list of installed updates, look for an item named Update for Microsoft Windows (KB948610) – this is the .NET Framework 2.0 SP2
6. Right-click on the item and choose Uninstall
7. Reboot”

So, the key to uninstall these beta bits from your Vista machine is to remove KB948609 and KB948610 hotfixes.

Apparently the fw. rollback healed our application. We will investigate this problem if it comes up in the RTM bits too (in few weeks I think). I hope it won’t. :)

Bocs, de ezt Aaron kérésére angolul írtam.
A lényeg, hogy ha Vistán le kell szedni az SQL 2008 RC0 vagy más által felrakott beta NET Framework 2.0 SP2-t és 3.5 SP1-et, akkor a KB948609 és KB948610 hotfixeket kell uninstallálni.

Could you hire me? Contact me if you like what I’ve done in this article and think I can create value for your company with my skills.