Notification center does not open Ever since upgrading to Yosemite 2 days ago my notifications no longer work. I can't even open the notification center by clicking the icon in the menubar. Nothing happens when i click it.

Anyone know what's going on or where to look to further investigate the issue?
I had the same problem and found an answer on this site. Did you ever use Terminal to disable Notification Center in and earlier OS? I did, and this tip brought it back - How do I re-enable Notification Center in Yosemite or El Capitan post-upgrade?