How can I make a disk utility boot disk for iMac with OS 10.7

Re-download Lion from your App Store purchases page. Install Lion on another drive.

If you have Snow Leopard installer disks for your model, you can use it instead.

I have HD corruption, and need to boot to my hidden drive and run disk utility, which is NOT possible in Yosemite. Is there another way to run disk utility on my internal HD, than creating an external boot drive of an old OS?

Why is that not possible?

Boot Using Command+R keys:

1. Restart the computer.

2. Immediately after the chime press and hold down the

"COMMAND" and the "R" keys together.

3. Release the keys when the Utilities Menu appears.

Have you not done this yourself? It is all over the internet that the recovery partition is missing. Booting to command+option+r boots to the cloud version of Yosemite, taking 20 minutes on fast internet. http://apple.stackexchange.com/questions/151072/missing-yosemite-recovery-partit ion

Yes, I have, and, I haven't seen that on my machines. I always do a clean install and I have a Yosemite Recovery HD. Of course I use COMMAND-R to boot from it rather than COMMAND-OPTION-R. In fact throughout the beta period I never saw a problem with the Recovery HD not being the correct version.

Well then, you can see on the internet, it is a big problem with the missing recovery partition. Also, keeping the recovery drive should not be dependent on doing a clean install.