参见“VS2010 Beta 2 Installed on a Previous Beta 1 System”

I had VS2010 Beta 1 installed. WhenBeta 2 came out today, I found I needed to uninstall Beta 1.Here are some things you have to watch out for:

1. You have to, of course, uninstall any extras installed after the Beta 1 install. This includes MVC, which is now in the boix.
2. The main uninstall of Beta 1 will ask you for a Beta 1 ISO, which is a real pain. The way to get around this is to do a manual install of the VS2010 TFS Object Model first and then it will be fine
3. The main uninstall of VS2010 Beta 1 will NOT uninstall all associated stuff
4. You must uninstall the VS2010 Beta 1 SDK by itself
5. Myself, and at least two other Tweeters got a complete Beta 2 install but it failed Silverlight 3 install, *even* though the SDK and the developer runtime *were* installed. It seems to notice it but instead of skipping over it, fails that install. I manually uninstalled the two, re-booted, and then did a re-install of Beta 2 but it did not pick up that it now needed the Silverlight 3 install. I went do dir\WCU\silverlight and manually installed the two files after the fact and it was fine. Someone else was able to just do a Repair after, re-boot and be fine.

All in all, pretty smooth given how large Beta 1 and 2 are and how many complicated pieces there are. I never seem to do fresh installs :)

BTW, lots of things have changed in Windows Workflow from Beta 1 to 2. I could not even open the project files. The project types have changed andMatt Winkler has promised me a post on that.