Recently, I've noticed a strange behavior on my iMac (Yosemite 10.10.4, Late 2009).
Everything freezes completely - it's totally unresponsive. HOWEVER, I can continue to control the mouse pointer perfectly.
In other words - even though I can move the pointer - I can't click any buttons, menu items, change the focus on any windows, or interact with the desktop, dock, menu, or any running app. Launchpad and Mission Control don't work. The iMac also doesn't seem to respond to the keyboard at all.
I should note that this happens very infrequently - perhaps once or twice a month. I haven't noticed a pattern of when it happens (e.g., it doesn't typically happen soon after restarting).
- Any idea what might cause this? I'm up to date on all my updates (OS X and apps), and I'm not doing anything out of the ordinary with my Mac (No envelope-pushing applications or modifications).
- So far - the only thing I can think of to fix this is hold down the power button until it restarts. Is there a better option? (E.g., on Windows, you have CTRL+ALT+DELETE, which seems to recover from any crash short of a full blue-screen). Is there an equivalent way to launch the activity monitor, for example?