Install Disk for Snow Leopard will not boot on an iMac 27in

Hi guys

You need to boot from the disks that came with your Mac, SL was released before the 27" iMacs so it cant boot them. Lion will be the first retail copy of OS X that will boot these macs. the copy of SL that came with your mac is 10.6.4 or something but the retail copy of SL is 10.0.0 it doesn't have the drivers for your mac to boot.

I would like to report back, I was able to install Snow Leopard (10.6.8) by using the target disk mode and running the Snow Leopard install disk from a different Mac computer. After running the retail Snow Leopard install, I updated with the combo installer to 10.6.8 and also updated all the other Software updates that showed up.

I now have snow leopard running on my iMac 27" that came with Lion pre-installed.

Fyi, I could not erase and reformat the SSD partition from the other mac, I had to log into lion to partition and format it before trying to run the Snow Leopard install.

So I hereby declare this thread solved.

I can confirm that this was the solution for me.

Had the exact same problem mentioned by everyone else. My problem is that I had been trying to boot up from the Snow Leopard disc I had purchased for my Macbook Pro.

The solution was booting from the grey OSX Install disc that came with my iMac. Worked exactly as it was supposed to.

Cheers @saxon !

Not quite accurate; the current retail DVD is 10.6.3. Result is still the same; you can't boot any Mac from an OS version earlier than that with which it shipped.

So DON'T lose the OE discs! (I keep mine in the safe).

The currently-shipping mid-2011 iMacs can boot Snow Leopard, even those that shipped from the factory with Lion preinstalled. The retail "universal" Snow Leopard DVD may not be able to boot them, however, as it has a version of Snow Leopard that does not include the necessary components for these iMacs. That makes getting Snow Leopard onto them and patched up to 10.6.8 a little tricky, but not impossible - just have to use another Mac to do the install with the new iMac in target disk mode, or restore from a bootable backup.

I had the same thing just happen to me after my iMac became unresponsive while I was I installing Silverlight in my Win 7 boot camp partition. After several failed attempts to boot normally (spinning wheel froze) I inserted my SL disk and attempted to boot from it. But like you I got the perpetual white screen. After thinking for a while, I decided to reset both my PRAM and NVRAM. After doing this, I was able to boot into the SL disk successfully.

I'm not sure which reset worked, but I'm glad I'm back running again. Good luck.

According to https://discussions.apple.com/docs/DOC-2455 you can install 10.6.x

As the original OS would have been 10.6.6 or 10.6.7 (probably 10.6.6 for a May model), there should be no problem installing and remaining at 10.6.7.

Note that the retail 10.6.3 won't work - to install from a DVD, it'll have to be the ones that should have shipped with the Mac (builds 10J4026 or 10J4139). The same build restriction will apply to TGM install, too.

I don't personally use Lion, which is I was quoting Kappy (who does).

However unless you've completely wiped the HD, you ought to be able to boot to the recovery partition by starting with the cmd and R keys held down (⌘R) and re-download Lion from there.

AS for SL, it depends what model your iMac is as to whether there's a possibility of installing it. See a.brody's article; https://discussions.apple.com/docs/DOC-2455 to identify if yours will.

It's unlikely you'd be able to do so from the disc, even the one that would have shipped with it prior to Lion, as a firmware update seems to have b••••••d that route.

However, provided the Mac is not precluded from doing so, you should be able to install from the 10.6.3 retail disc to an external HD and update that to 10.6.8 and use that to boot from.

See Kappy's post here; https://discussions.apple.com/thread/3659568?answerId=17330084022#17330084022

Yes, it is ridiculous how it is impossible to install Snow Leopard. I have two Snow Leopard DVDs: one that I purchased for a Macbook soon after it's release (10.6.0), and one that came with my iMac (10.6.4). Both of these boot up my Macbook (running 10.6.7) just fine. My SL 10.6.0 DVD mounts onto my iMac (Lion 10.7.0), but you cannot run the install. I attempted to boot from this DVD and got the infinite white screen and Apple logo, as some have reported above. The other SL 10.6.4 DVD will not even mount in Lion, and will not even show up as a bootable drive when I attempt to select it after holding alt/option on reboot.

I created a bootable external drive from SL 10.6.0, attempted boot, same infinite white screen/apple logo.

I created a bootable external drive from SL 10.6.4 on my macbook. I attempted to boot from this drive, and got the white screen of death, except that this time I actually got the loading symbol underneath the Apple logo. After about a minute of attempting to boot, the Apple logo changed to a circle with a diagonal line through it (the "NO!" sign).

I took my iMac to the genius bar. They inserted SL 10.6.0, which would not boot. Then they determined that my computer had to run 10.6.4 and later. So, they restored an image of SL 10.6.4 onto my partition (not an install from an image, but an image of SL already installed). Hurray! Snow Leopard was successfully shoved onto my iMac!

I then deleted a third partition on my hard drive I did not need anymore, which somehow screwed up my SL partition (even though it said "Will not erase partition SL or Macintosh HD). Now I am back at square one, and I guess I need to take my flippin iMac back to Apple for them to do what I should be able to do.

I like Apple, but sheesh do I hate Lion right now.

I am glad that I have found this thread (which is covering more then 2 years, but who cares ;-). The information in it is very valuable to me.

I finally realize after a half a day of fiddling and wasting my time thinking that there was some kind of disk reading problem that there actually is a minimum OSX version needed when reinstalling OSX depending on the Apple product! In my case, it was driving me nuts why I could not start the DVD that came with my older MacBookPro to freshen up my girlriend just-al-little-newer MacBook Pro nor an external drive with a 1:1 copy of the disk (using SuperDuper).

This now demystified issue could be prevented by Apple by implementing a little bit of user interfacing with the one that "accidently" inserts an OSX installation/recovery disk! Something like: This Mac requires at least OSX version 10.6.3, you have inserted 10.6.0 would cut it.

i was having similar problem on 13" MBP i5 (early 2011). The mac os x install disc is 10.6.6 version 1.

try pressing Option when boot up, select the DVD and press CMD V to go verbose mode.

What i saw was alot of disk1s0 errors. However the DVD drive is working properly before so it must be the disc's problem. But the disk reads properly in my other PC...

I then clone the disc onto another Dual Layer DVD with x4 speed. And the cloned disk works without a hitch.

Very strange problem. I believe the original disc was not burned properly by Apple.

You wouldn't believe what I had to do.

I installed Snow Leopard on an external hard drive the same size as the one in my 27" iMac from a computer that could boot the disc. I then updated to 10.6.8.

I then hooked that drive up to my iMac, booted into my Lion disk utilities and used the restore tool to copy the external hard drive to my internal one.

It took all day... in fact... my disc is still restoring as it takes about 12 hours to restore 1TB from one drive to another.

Wouldn't matter - you'd still have to buy a retail version of the OS. You cannot install OS X from a DVD which shipped with one Mac model onto another Mac model, regardless of relative age. The discs are (deliberately) model-specific.

Call Applecare with the serial no. of the Mac and they can replace the original discs for a shipping and handling fee.