Loaded macOS Sierra this morning. Now, once VMWare is running, cmd+tab switches me back to the mac environment but system immediately and automatically switches me back to vm. Result? Can't access mac environment when vm is running. Help?
Force quit Dock from Activity Monitor. Dock automatically restarts, and Cmnd+Tab should now work. Some glitch with Dock, it seems. Worked for me.
In my case, I wasn't even able to open the Activity Monitor (or the Launchpad)
I had to use the terminal to kill the Dock process, it restarted automatically after a few seconds
In the terminal, type:
ps aux | grep -i dock
Note the PID (2nd column) of the process named: "/System/Library/CoreServices/Dock.app/Contents/MacOS/Dock"
Kill that process:
kill pid. E.g. if the PID was 708, run
Apparently, Sierra set the keyboard preference to a loop. Turned that off and everything worked as usual. (Detailed path: system preferences>keyboard>shortcuts>input sources) Both boxes were checked. I unchecked both.
Launch Activity monitor, then select user tasks, and shut down the process called 'dock'. This worked like a charm for me. Problem solved, instantly. Well, it took about ten seconds while the dock rebooted itself, then command tab worked like a charm as usual, no restart needed.
I have found that when you're running a Virtual Machine manager like VirtualBox sometimes an open Virtual Machine window can grab the ⌘ key (which is often used switch between VM keyboard capture mode).
In this case you can fix it by bring the VirtualBox Console window up (e.g. using the Dock bar icon) and tap the ⌘ key again and it should release it properly. With VMWare the settings may be different but it's worth looking at the keyboard capture/mapping options to see if a similar thing is happening.