Disk Utility: "Modifying Partition Map"

It's most likely stuck and not going to finish. I experienced this once while creating a new partition for testing purposes. Force quiting will loose any unsaved changes including a partition that's being modified but it looks like your only option at this point. It should not affect your current Mac partition however I'm unsure if it will affect your XP partition. Boot camp works well but in general I would say it's not a good idea to try and re-size or split existing partitions that have data. To do what you want to do you could use Boot camp to create another partition but it would only take the space from your Mac volume. You would probably have to backup or make an image of your XP system then start over using Boot Camp to create the 2 partitions of the size you want.

FYI: You would probably have a better chance getting an answer for this question over in the Boot Camp forum.

George

From Disk Utility it should take not more than a minute or so unless you have chosen to zero out the data or do a secure erase. I'm not sure how to modify a partition in Windows.

George

When you say you restored it to normal do you mean normal as in before you attempted to create a third partition or normal meaning back to only your Mac partition? It may not work because you are trying to add a partition to a volume that has already been formatted NTFS+ and it's possible that Disk Utility will not be able to do it.

George

You might try zeroing out the data on that partition by going to erase under disk utility and erase free space or erase in that partition. Might have a bad block that erasing the partition will take care of.
I also find that windows partitions or virtual drives crash a whole lot, keep a full backup somewhere with CCcloner if you haven't already.