I have heard from and read about problems reported by several customers who are running into package load failure errors in the Visual Studio IDE after migrating from beta or CTP builds of Visual Studio 2005 and the .NET Framework 2.0 to the final release. I previously posted this blog item with some suggestions about how to resolve this. I finally found a machine inside of Microsoft that reproduced the same symptoms and was able to track down another possible root cause and fix that the current cleanup tools do not seem to handle in all cases.
The machine I looked at today had some orphaned beta assemblies in the GAC. Because those were present, the native images generated during setup for the final release of VS 2005 contained references to these orphaned assemblies. Then, when the VS IDE attempted to load packages at startup, it started loading these native images with invalid references in them and failed with one of the infamous Package Load Failure error dialogs that looked like the following (the exact package that fails to load will vary, but the rest of the dialog will look similar to this):
I had to close Visual Studio and then run the following command line to clear up these package load failures:
rd /s /q %windir%\assembly\NativeImages_v2.0.50727_32\Microsoft.VisualStu#
If you are running into package load failures on your system after installing the final release of Visual Studio 2005, I encourage you to first try the troubleshooting tool, and then try the above command line. If all of those fail, then please proceed to step 3 in this blog post (which I've also updated to include this command line as step 2).