I had this same problem. The solution can be found as the second item
on the following page:
http://lab.msdn.microsoft.com/produc...ID=FDBK24236#2
FDBK24236#2: Duplicate Assemblies
Workaround Description:
The Problem arises from 2 assemblies of the same name /version but are
infact different.
Workaround Steps:
Open Windows Explorer and navigate to C:\Windows\assembly
Locate the Microsoft.VisualStudio.Shell.Interop.8.0 assembly name
There are two assemblies with the same version
Right click to Properties on each and remember the older of the two's
last modified dates
Right click the older of the two and select Uninstall
Once I closed the IDE and reopened, the designers worked as expected.
