Running into a new and extremely frustrating problem where my mouse is completely jerky in the movements. The pointer jumps from place to place and isn’t smooth. I’ve cleaned the mouse from all the lint, tried a different mouse, moved the external hard drive and other devices even tried with everything unplugged from the back of my iMac. All things that a google search seemed to indicate might be the problem.
I’ve run activity monitor and there isn’t a backup or time machine task running in the background when this occurs. I believe this started in earnest when I did the last security update 2020-01 from February.
Hi OogieM One item to check is look for any programs or apps that use bluetooth. I installed a Android file transfer program trying to help a friend get some pictures off her phone. I had bluetooth problems with my mouse and keyboard. Once I uninstalled that program and rebooted my mouse and keyboard problems went away.
I recently had the WiFi/Bluetooth controller on my iMac go out. First the WiFi refused to turn on, then I started noticing the jittery mouse. Got on the phone with Apple and they the two issues are related and I’ll need to have it repaired (out of warranty). For now I’m using Ethernet and a wired mouse and keyboard, and I am actually really enjoying the experience and responsiveness. I’ll need the repair eventually but I’m putting it off until summer when things slow down. I live about 150 miles from an Apple store, so it will be an authorized repair shop for me.