While working in Visual Studio, there are few things worse than being unable to open a WinForm and seeing an error like this:
I was working on a VS Tools AddIn and when I attempted to open a form, this screen was displayed. It had this error message.
Could not load file or assembly Microsoft.Dynamics.Framework.UI.WinForms.Controls or one of its dependencies
I hate this error window in Visual Studio, because most of the time I have no idea what the problem is or how to resolve it. I can deduce that there is some problem with the form, but that's about it.
Fortunately, in this case, the error was specific enough that I knew it had to do with some GP WinForm components. And even more fortunately, a Google search turned up a forum post where someone else had experienced the same error.
Thankfully, that user had solved the problem and was nice enough to post the solution: Reinstall VS Tools.
I nervously reinstalled VS Tools for GP 2013, and behold, I could open my form in Designer mode in Visual Studio again.
Whew. Crisis averted.