Disk Utility refuses to work because of Lion!

Question

I want to resize and add a partition (i.e. split a partition into two smaller partitions) on my hard drive, and I get the following error:
“Partition failed with the error: This operation requires a newer version of Mac OS X for this disk”
This is interesting (and annoying) because I used this exact computer and OS X version, 10.6.8, to format and partition this drive in the first place.
The reason must be the copy of Lion and/or the copy of the Lion installer (the full, “offline”-enabled installer that I made with the help of instructions) that I cloned onto the drive with Carbon Copy Cloner. I also cloned the Lion Recovery partition over. It probably also matters that I booted from all three partitions once (to test that they worked).
So...
what did Lion do to the partition map or whatever that causes the 10.6.8 Disk Utility app to no longer be able to change it and why?!
how do I undo this so I can use 10.6.8 Disk Utility to modify the partitions again?
I know I could just use 10.7's Disk Utility to get the job done now, but I don't want to be dependent on “OS X Vista” in the future.

Answer 1

You do not have to erase the HD. The problem is almost certainly the presence of the hidden "Lion Recovery" partition -- the Snow Leopard version of Disk Utility doesn't understand what it is so for safety's sake it won't let you change the partition map.
If you are willing to sacrifice that partition, you should be able to use Snow Leopard's Disk Utility to do what you want, although I can't guarantee this will work, or that it won't cause some unexpected problems with Lion. However, I have done this with a drive that originally had both Snow Leopard & Lion on separate partitions that I wanted to dedicate to Snow Leopard only, & it works fine for that.
With that understood, you can do this in Terminal. First, use "diskutil list" to get the IDENTIFIER value for the Lion Recovery partition. An example would be:
3: Apple_Boot Recovery HD 650.0 MB disk1s3
The IDENTIFIER value here would be disk1s3.
Now, erase the partition, converting it to a normal HFS+ volume Snow Leopard's Disk Utility will understand, with the following command, replacing {IDENTIFIER value} with what you got from the list command:
diskutil eraseVolume HFS+ Blank /dev/{IDENTIFIER value}
An example would be:
diskutil eraseVolume HFS+ Blank /dev/disk1s3
IMPORTANT!! The previous step erases the contents of the partition. If you use the wrong IDENTIFIER value, you will erase the wrong partition, leaving you with a drive that won't start up your Mac, no data, etc. If you are not sure about this, don't try it! You really shouldn't be doing this OR resizing partitions without a backup, but if you are unable or unwilling to back things up, this is your only alternative.
At this point, quit Terminal, launch Snow Leopard's Disk Utility & confirm that it shows a new partition named "Blank," which should be about 650 MB. You should now be able to use Snow Leopard's Disk Utility to resize partitions, delete the "Blank" partition, etc.