I've had very bad results using the latest variation of Disk Utility. It has ALL sorts of problems trying to partition and erase. I very rarely get though an erase on the first try. It'll nuke the partition table and then puke up an error and I have to retry it usually. A few times I've had to drop into terminal and spam some zeros onto the platters to get it to quit trying to "adjust" it and just get on with the formatting. Completely unacceptable behavior for what should be a user-friendly noob-facing application.
I just got a new laptop to replace my aging 2012 Macbook Pro, and I encountered the same thing while trying to format an external USB hard drive.
Not only that, but I learned something else: the latest Disk Utility will often report that it successfully did something that it did not, in fact, do. For example, if you try to change the size of a partition on an encrypted disk, Disk Utility will say "Success" but do nothing; the partition size will not be changed. Disk Utility is incapable of changing partitions on an encrypted disk, but
nowhere is this documented, and you will receive no warning that you can't do this if you try.
