Had a successful conversion of the DB from version to version (needed to fix Digest email send and the only way was the latest build). I can nav to pages without issue, however any postback is causing a control tree error. I am using the BIN build and simply replacing the config files, so I should be good to go.

Anyone seeing something similar?!

http://forum.yetanotherforum.net/yaf_postsm59613_PostBack-ViewState-problem-after-upgrading-to--NET-4-0.aspx . Any help would be appreciated.

I figured it out. We are using Modernizr on the site and the code was placed at the very bottom of the page, right before the closing body tag. Moving it to a different location resolved the problem.