This is the first time we receive such error report for the AppBuilder Simulator. Performing a search about the exact exception message, I found the following article
. It makes me think that if you clear the Simulator's cache, the faulty behavior should correct itself. Could you please close any opened VS instances and then, delete the whole %localappdata%\Telerik\BlackDragon\Cache
folder on your machine and try again?
Please, let me know if the issue is still present after that.