In Microsoft Project, both 2007 and 2010, we have multi level undo. One way this is used by many customers is for what-if work – change things around and see what affect this has on the schedule – then use multi-level undo to get back to the starting scenario. If you use it in this way then there is another feature of Project you should know about – and avoid: Auto-Save. The behavior of undo, auto-save and save is different in Project than other Microsoft applications. Project clears the undo buffer on save and this is one reason that auto-save is not turned on by default.. If you turn it on then you need to be aware that if the auto-save kicks in then you could lose the opportunity to undo changes. Some customers like this feature in other Office applications, and use a Group Policy to ensure this is set for all users – and all applications. This can catch users out who might want to use the multi-level undo as a what-if tool – and if so then you would not want to force this option down to your Project users. And before you ask – this isn’t a bug – it is just the way Project works.