the mouse on my Mac is very jerky and when moving from one window to another will jump to a different location on the screen, it is a late 2010 iMac with the latest software and updates.
What happens with a wired mouse? If you don't have one, log into a newly created admin user account and see if the problem persists.
I'd recommend starting by doing a SMC reset, if it doesn't work the first time do it 2-3 more times. You can find directions by clicking Intel iMac SMC and PRAM resets
I seem to have solved the problem bu using a dull black mouse pad (plastic notebook cover) this seems to solve the problem immediately, now i will spray paint my old mouse pad and see if that will work too as the binder cover is a little cumberson
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