I just briefly suffered and then found a solution for a new-to-me Mac problem: Notification Center stopped working. Clicking on the Date and Time in the upper-right-hand corner of my display did not yield the expected result of showing my notifications. Another weird side effect that I didn’t grok immediately but noticed later was that the widgets I had placed on my Desktop weren’t showing. Lastly, clicking on Notifications in System Settings didn’t do anything: didn’t load the options, nuthin.

I dug around on the internet and found a few troubleshooting steps that didn’t work, and I even decided to reinstall macOS on the MacBook last night. Nothing worked (in addition to the macOS reinstallation, I found myself deleting the Notifications plist file).

I did a quick web search this morning over coffee and found a Reddit thread that led to this Apple discussion of the problem. The solution, it turned out, was to delete all of the files in a folder in your home library folder:

Try removing all files and directories from here:

/Library/Group Containers/group.com.apple.UserNotifications/Library/UserNotifications/Remote/default

if doing so in Terminal you will need to grant Full Disk Access to Terminal first in System Preferences -> Privacy & Security

I emptied out the folder using Finder and rebooted, and voilà! everything is back to normal. I was pretty sure I was going to have to move all of my stuff over to a new user account, but this is a happier resolution.