Problem: When deploying a soluction in VS 2010 I get the following error.
"VS Error: Error occurred in deployment step 'Activate Features': Failed to activate feature 'XX' (ID: xxxa2e8a-78d7-451c-aa85-3d28555e5555) at scope 'http://demo.dev'."
ULS contained the following error "Feature Activation: Threw an exception, attempting to roll back. Feature 'XX' (ID: 'xxxa2e8a-78d7-451c-aa85-3d28555e5555'). Exception: System.InvalidOperationException: Failed to activate feature 'XX' (ID:xxxa2e8a-78d7-451c-aa85-3d28555e5555) at scope 'http://demo.dev'. at Microsoft.SharePoint.SPFeature.HandleActivateError(SPFeature featError, Int32 iRetVal, Boolean fForce)"
Initial Hypothesis: Performing an IISreset did not resolve my issue, the suggestion to manual start the feature will activate the feature however it does not solve my deployment issue from VS. The feature is scoped at 'Site' level so activating the feature can be done at the site collection level.
Resolution: Removed the feature and solution using Powershell Rebooted Visual Studio development environment Open solution in Visual Studio 2010 and redeployed. The cause is still not know however, rebooting and uninstalling the solution has fixed the issue.