For past 2 months I randomly get system hanging, sluggishness and jerkiness forcing me to reboot or wait for it to pass on its own. I've uninstalled some 3rd party apps I wasn't using, did a permissions fixes. problem went away for about 3 days then today it's happened twice in 3 hours. I decided to test a theory that its a bluetooth issue while the issue was going on. Turned off the trackpad for 5 seconds restarted it no more issue. I think I have a defective trackpad. If I take it to the apple store will they replace it? I've had since Oct 2011.