Cmd-Tab suddenly stopped working, and my Dock is unresponsive, what do I do?

"Your Dock has become unresponsive. It's rare, but it does sometimes happen. To fix it you just need to kill the Dock app and it will automatically restart. To kill the Dock:

Go to Applications ➔ Utilities ➔ Terminal.app

Type killall Dock

If that doesn't work, type killall -9 Dock

The Dock will vanish for a few moments and then pop back up good as new. None of your apps should be affected.

Edit: sudo killall Dock would kill other users' docks, and isn't even more likely to work. Thanks derober for pointing that out. killall -9 Dock is the right command"

"Another option for reference purpose for those that do not want to use terminal and this works even if the dock is hanging:

Alt+Cmd+esc will open the Force Quit Applications window and you can kill finder from there. Also right-clicking on the dock area should popup a Force Quit option if the dock is unresponsive.

This is an alternative for those that can't find their way around in the terminal"

"Had the exact same problem, ended up finding solution on Apple support communities discussions.apple.com/thread/3384782?start=30&tstart=0

Summarized below, thanks to watski

I deleted ~/Library/Application Support/Dock/*.db and killed the Dock
in Activity Viewer. Now it seems to behave. For the record I tried
deleting the dock .plist, setting VMWare preferences and so on but in
vein. Rebooting did not help either."

"On your Mac:

Navigate to System Preferences
Go to Mission Control
Uncheck ""When switching to an application, switch to a Space with open windows for the application"""

"Your Dock has become unresponsive. It's rare, but it does sometimes happen. To fix it you just need to kill the Dock app and it will automatically restart

The Dock is launched as part of Finder, so you can just relaunch Finder from the ""Force Quit"" menu, which is accessible via with Cmd + Alt + Escape"