My reboot solution lasted 24 hours. So when I have my return call with Apple tech on Monday about this issue I will tell them the following.
• Since all widgets and services appeared in my Guest user, I rebooted and discovered that the missing widgets appeared in Notification Center for my user. Also, the share button no longer said "No Service". Success!
• A little under 24 hours later I went to remove a widget and watched all the widgets I hadn't installed yet disappear in front of me from the widget list in the Notification Center. The Weather and Social widgets also disappeared from Today. They only appear if I select "Edit", but There is a gray box on the gray Notification Center that shows where they used to be. They may even be there, but hidden. The widget I removed disappeared as well. Sharing services also disappeared. Now back to "No Service".
• Opening up Activity Monitor, I force quit Notification Center. My deleted widget returned, but not the other uninstalled Apple widgets. The installed Apple widgets of Social & Weather also did not return to the Today panel.
• Following a tip online, I discovered the Widget Simulator. I ran the Weather widget in it. Weather returned to my Today panel. There is no Social widget in the
/System/Library/Frameworks/NotificationCenter.framework/PlugIns/ folder, so I can't do the same trick for it. Sharing still says "No Service". This trick seems to work for me only if I force quit Notification Center.
• My only option is to reboot again, but this is not an optimal solution. I have a web server running as well as a ZNC server. Neither service auto runs anymore since upgrading to Yosemite. None of my launchd agents seem to be running, which could either be related to this problem, or be another bug entirely.
I'll post an update here. We're on the cutting edge on this so I am not expecting a lot of help. When I called Apple for help on Friday, the guy who first helped me had only installed Yosemite on his system 20 minutes before I called. I was his first Yosemite trouble call. He escalated me to a different tech who didn't have Yosemite installed yet. Nice guys, but :roll eyes:. I am very curious to know if they Widget Simulator solution works between reboots.