Unable to load assembly group - Sandbox solution
I ran into an error lately when i tried to add a web part which i created as a Sandbox Solution. It said Unable to load assembly group. The user assembly group provider threw an exception while trying to provide user assemblies for the specified assembly group To resolve it follow the below steps 1. Go to services.msc 2. Check the service account for "SharePoint 2010 User Code Host service" 3. Change it to a domain account or probably to the farm account.