How to delete a hard drive that is corrupted with Yosemite. . .

Internet recovery will (option-r) give you window with disk utility you can erase your HD from here or repair etc. How do you plan on installing Mavericks etc.? You can also install your Time Machine Back up from here to get you back to your original set up.

On start up hold down option-r when grey screen appears as Apple states. Some have said command-option-r, have tried both see no difference. Sounds like you are booting Yosemite? Is your Flashdrive a installer for Mavericks. Go to OS X Daily web site and search for flash drive install Mavericks. You could try install OS from internet recovery but I am not sure if it will give you Mavericks or Yosemite. Some have had good success with internet recovery and others mixed. Age of Machine may be factor. I was used my old 2008 iMac and could not recover Mavericks but could erase HD. You should be able to erase HD. Good Luck.

First, there is a definite difference in the recovery options:

Command + R invokes a local recovery and the currently installed OS will be reinstalled.

Command + Option + R (Internet recovery) connects you to Apple's servers and, after reformatting/erasing your hard drive, it should reinstall the original OS version (if Lion and later). If the original was Snow Leopard or earlier, that will not work as you will need the original install disk.

See here:

OS X: About OS X Recovery

Second, you cannot erase a hard drive you are booted from. You need to be booted from another source. So, either use recovery, your original install disk, or a bootabe clone to boot into. Then you can erase your hard drive and reinstall. And, you must erase your hard drive first if you wish to go "backwards" - that is the only way.

Your Mac is too old to use recovery:

Computers that can be upgraded to use OS X Internet Recovery

Dwightman wrote:

How does the system understand the gist of what I am saying. It struck the word ***** from my previous and initial question. Is this a thinking machine? The new OS, Yosemite S - U - C - K - S- . . . .

There are filters here on these forums and anything that violates the ToU will be removed.

Thanks for some good info babowa. Personally I think the clone and time machine are the way to go. Have not tried internet recovery on my new iMac. Got option-r from Apple on erase HD before selling or donating Mac.

That would be either:

Option key = brings up startup manager giving you a list of available disks to boot from

or

Command + Option + R = Internet Recovery; required to erase and reinstall the original OS (if Lion or later) when selling. If the Mac came with install disks (Snow Leopard or earlier) you will need those; recovery will not work in that case.

or

Command + R = local recovery; will reinstall the currently installed OS version; fine for just a reinstall, but does not comply with the licensing terms when selling since you're obligated to erase any OS obtained from the app store as it is not transferable and tied to your Apple ID.

If you have an old iMac and don't have Snow leopard install disk. Go to Apple store search Snow Leopard and you can buy ( $19.99 & free shipping )install disk which you can erase and install Snow Leopard 10.6.3 which will upgrade to 10.6.8. Giving you the ability to upgrade. Interestly mine was earlier and of course lost my Snow Leopard install disk and option-r did allow to disk utility but of course no OS which I learned. Bought Snow Leopard so I could donate clean machine and give install disk.

Yes, the retail disk will work if the Mac came with 10.6.2 or earlier; it will not work if it came with 10.6.4 or later as Macs cannot boot from an OS version older than what they came with. My mid 2010 came with 10.6.4, so I am not able to use the retail version. Not sure if it would work if it had come with 10.6.3.

Apple's design from the earliest days will not allow you to install an OS that was earlier then what the computer came with. This always made me stay with a machine longer then I wanted. In the old days software was more likely to not work. I happy that most software I ran under Snow Leopard works with Mavericks on my new 27" iMac. As I hear more about Yosemite I will upgrade when I am sure it is free of problems. When I was younger I was more likely to go right for a new OS. I had problems so now I am more willing to wait a little. Of course, now I am mostly using Apple's Apps. Age does have some advantages. I still like the idea of an install disk or disks coming with the computer. It would be worth the expense to me. But that's me. And something that is history now.

Some of my apps (and they are actually Apple's) no longer run in Yosemite (an older iMovie version, iDVD (glitchy) and my retail version of Aperture, so I will not be installing Yosemite on my iMac which is what I use for my video projects. It is running on my MBP though where I don't need those applications.

Thanks for info. I use mostly Aperture now and may do some video work in the future. I used Final Cut Express in Snow Leopard its seems to run in Mavericks but I have not really used it kinda doubt it runs well from what I've read in the long run and isn't supported. So that I would upgrade if I decided to go back to video. But I to will stay with Mavericks now. I think iDVD is no longer supported by Apple. I think people are going to Toaster but not sure. Good Luck.