Same thing happened to me as Chocwise 100%, except when I googled it I
found the solution on this page.
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System -> Quit takes a long time to appear
https://bugs.launchpad.net/bugs/123078
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Desktop Bugs, which is a bug assignee.
I have this problem in Fiesty! I can only confirm it for cd's since I
have only a cd burner. This has happened when using Rhythmbox for audio
cd's, and the Nautilus front end (Places > CD/DVD Creator) for data
cd's, and when I right click on an .iso and chose Write to disc... It
even happened, IIRC
