rundll32.exe invagent.dll eating 100% CPU

Opt out of the Windows Customer Experience Improvement Program and uninstall KB2976978.

The offending invagent.dll is part of Windows Update KB2976978, which seems to be about gathering app compatability telemetry in preparation for Windows 10 upgrades. Only users who opt into the CEI are offered this update.

By uninstalling the update (and opting out so I'm not re-offered it), invagent.dll was removed from my system and the scheduled task.

To opt out:

• Open Control Panel
• Navigate to Action Center, Change Action Center Settings, Customer Experience Improvement Program Settings
• Select, "No, I do not want to participate in the program."

To uninstall the update:

• Open Control Panel
• Navigate to Programs and Features, View Installed Updates
• Locate Update for Microsoft Windows (KB2976978), right click, and select Delete.
• You will be prompted to restart your computer.