set property 'system.windows.resourcedictionary.deferrablecontent' threw an exception

Question

I'm running Visual Studio 2012, when I add a new File/Reference to a project the message box appears showing the error message

set property 'system.windows.resourcedictionary.deferrablecontent' threw an exception

I read an MSDN article suggesting to run the command devenv /resetuserdata on visual studio command prompt to resolve this problem, tried it but didn't work for me. In fact the command prompt shows the Unknown Error message.

Answer 1

Some addins cause this issue for me so have had to workaround it whenever it occurs:

In Vis studio -

Tools > Options > Environment > Add-in Security, uncheck 'Allow Add-in components to load', OK

Restart vis studio

The error shouldn't occur anymore, so go back to

Tools > Options > Environment > Add-in Security and re-check Allow Add-in components to load, OK

To be specific, I get this error when trying to add files to projects and manage Nuget Packages.

Update

I now make a point of opening 'Tools > Nuget package manager > Manage nuget packages for solution' whenever I open up a new instance of Vis studio, before loading a solution, just to make sure the window loads properly

That way I know I won't get this issue.