PROBLEM: My cursor freezes every second for about a quarter second when moving any mouse and the top 20 hits in searches for "capitan mouse freeze" have not given effective advice. BACKSTORY: Magic Mouse (v1) had been running flawlessly on my 2014 iMac until I installed the latest El Capitan 10.11.6 security patch (2017-001) and rebooted this morning. Freeze happens with my Magic Mouse (1) via Bluetooth AND ALSO with my wired Logitech mouse with Bluetooth is disabled, or all combinations tried. All other Bluetooth devices are disconnected, USB mouse was plugged in through wired keyboard connected directly to iMac with no other USB devices connected. During freeze, bluetooth mouse halts and recovers near the freeze spot, however USB mouse jumps leagues across screen ~ very difficult to use. ATTEMPTED: * I have removed Magic Mouse preferences and rebooted * uninstalled Logitech control panel * toggled MagicPrefs on and off * removed Magic Mouse pairing, and re-paired The freeze only happens on mouse movement, and scrolling does not seem to be affected. Activity Monitor shows nominal CPU usage, nothing out of the ordinary.