On Fri, April 27, 2012 04:15, Shaun wrote:

Well this is it. I've used both 'remove' and 'history undo' and had better success (system not having something important removed) with the latter.

I have only this suspicion. It may be that yum history undo only rolls back the changes actually made by the previous yum update/install since it 'knows' that the system environment has not changed in the interim. Whereas yum history remove, since it has to cherry-pick packages from a possibly changed environment, instead removes rpm dependencies based on the package specs of the items directly added by the original yum command, whether these were installed in that transaction or not.

But, this is only a guess.