LightSwitch error when trying to use the runtime Design Screen feature

I get the following error, when trying to use the runtime screen editor. (LightSwitch 2011, RTM version)

"The last change wasn't successfully persisted. Please shut down the running application. Error: Object reference not set to an instance of an object."

This happens after making any 开发者_开发技巧change and saving. I've tried creating a new project with a single table and a single screen. Same error.

Found the solution. Delete the following directories:

%LOCALAPPDATA%\Microsoft\VisualStudio\10.0\ComponentModelCache
%LOCALAPPDATA%\Microsoft\VisualStudio\10.0\ManifestCache 

Source here.