This error can occur when Xamarin Studio fails to load key add-ins. MonoDevelop appears because it's the foundation underneath Xamarin Studio.
Important note Unless you've manually edited the add-ins or something similar; this is most likely caused by a bug. In this case, please contact support, or file a bug. Especially if the workaround described below is ineffective.
Usually this issue can be resolved by the following steps:
- Closing Xamarin Studio. (aka "MonoDevelop" per the symptoms)
- Delete the Xamarin Studio Cache from your machine:
- Restart Xamarin Studio.