Comment 3 for bug 617257

To see what's the problem, please paste here the content of ~/.config/gtg/gtg.conf
You should find at the bottom of that file something like this:
...
[plugins]
disabled = ...
enabled = ..., notification_area, ...

If this problem is originated from the bug I'm thinking about, it should go away just by closing GTG manually (Tasks->Quit) before shutting the computer down. Please confirm if this fixes the problem.