Rich Dougherty

100% CPU with UserEventAgent

My Mac laptop has been running hot, with the UserEventAgent process pegged at 100% CPU.

This is apparently due to a bug in the interaction between the AppleHIDMouseAgent and some mice and keyboards. In my case it is probably my Kinesis keyboard.

The fix is to disable the AppleHIDMouseAgent plugin and restart the computer.

sudo mkdir /System/Library/UserEventPlugins.disabled
sudo mv /System/Library/UserEventPlugins/AppleHIDMouseAgent.plugin /System/Library/UserEventPlugins.disabled

Note: renaming the AppleHIDMouseAgent.plugin within the same directory won't work—it will simply prevent your computer from booting. :)