How to resolve VS2010 Windows Form Designer issue (base class could not be loaded)

Question

I have recently been getting an error in the Windows Forms designer of VS2010SP1 when using inherited UserControls.

The error is

The designer

Answer 1

I had the same issue. I had a Form object/base object I was inheriting from, and all of a sudden I see this message for all Forms that were inheriting from the Base.

I tried to backtrack and figure out what changed recently and remembered I set my project Platform Target from Any CPU to x64. I changed it back to Any CPU and the problem got resolved, and then setting it back again to x64 still kept the problem fixed.

This was on VS 2013, by the way.