R6034 - An application has made an attempt to load the C runtime library incorrectly

[This was originally posted at http://timstall.dotnetdevelopersjournal.com/r6034__an_application_has_made_an_attempt_to_load_the_c_run.htm]

A coworker recently got this error when trying to open a web application project within Visual Studio 2008:

Runtime Error!

Program: C:\Prog...

R6034

An application has made an attempt to load the C runtime library incorrectly. Please contact the application's support team for more information.

Note that in this case, (1) Visual Studio opened just fine, (2) the problem was in merely loading a web project, and (3) nothing was even being compiled yet.

It turned out the problem was likely from a corrupt uninstall of the .Net 3.5 SP1. By re-installing the SP, things began to work again.

NOTE: .Net 3.5 SP1 has a potential error with the web dlls, so you may need to make some tweaks to the GAC.