Mission Control not working after system upgrade to macOS Sierra Today I had changed my MacBook Pro early 2011 hard drive for a SSD, and did a clean installation of macOS Sierra. Everything is working like a charm, except for the Mission Control, when I try to execute it via Trackpad shortcut or App in the Launchpad, it restarts me the Dock. That is an unexpected issue, and I'm want to know if someone encountered this bug before!
I had a similar problem with a Mac Book Pro (late 2011). I did a clean installation of macOS Sierra and Mission Control and Launchpad were not working, but it did not restart the Dock when I tried to open any of them. I researched a bit I tried killall Dock on the Terminal, for restarting it manually and that worked for me.

Give it a try. Maybe doing it manually will make it work.