Snow leopard install cd stuck in a Leopard iMac after a failed install

Nov 18, 2011
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The main issues is a snow leopard install disk that is stuck in a recently erased (zero'd out) leopard iMac, it keeps booting from the cd and I can't eject it.

Here's my situation:

I work for a college and we bought 2 new iMac's with Lion, for a total of 4 iMacs.
1 iMac Leopard 10.5.4
1 iMac Leopard 10.5.8

I have an iMac at home running Snow Leopard 10.6.2 updated to 6.8
I only have 2 installation disk sets: 10.5.4 & my own 10.6.2 disks
The other 10.5.8 disks seemed to be lost by the person working here before me.

All the students work is backed up but I don't use time machine. I have 2 external hard drives with plenty of free space. But I think for this problem I may have to use time machine for the first time, but I've already told time machine not to use these 2 external drives.

There's also a MacBook running Snow Leopard 6.8, no problems there, just want to upgrade to Lion

Here's what I wanted to do:

Update everything to Lion, including my personal computer
I know you need Snow Leopard to jump to Lion
But I would settle for at least getting the 2 work iMacs updated to Snow Leopard
Or even less, I would be happy with just reformatting with them Leopard so they're clean for the next semester, but I'm missing 1 set of install disks, 10.5.8.

So I'm only focused on fixing the 2 iMacs running Leopard.

Here's what happened:

So I tried my Snow leopard disks and they didn't work
"Mac OS X can't be installed on this computer"
I tried my 10.5.4 disks on the 10.5.8 iMac, and it didn't work
The 10.5.4 disk not working on a higher version makes sense to me,
but why can't I upgrade from Leopard to Snow Leopard with the cd

Without the 10.5.8 disks I decided to leave that machine alone, before I did more harm then good.

So now I'm only working on the 10.5.4 iMac because I have the original install disks.

I used disk utility during another failed snow leopard install.
I erased not only the "macintosh" partition but also the entire hard drive.
I also zero'd out all the data in an attempt to get snow leopard to work.
At this point the snow leopard disk is in the machine and I restarted it hoping that Snow Leopard would install but nope "Mac OS X can't be installed on this computer".

Here's the problems:

1) Why won't a snow leopard disk work on a leopard machine even after I formatted the drive?
If I could install snow leopard using the disk that is stuck in the machine then it would just eject itself during the intsall, problem solved.

2)How do I eject a disk that is being used as a boot disk?
The snow leopard install cd stuck in the zero'd out leopard iMac,
if I could get the cd to eject then I could reinstall leopard and forget about this mess.

3) Could I use time machine to back up the 10.5.8 iMac and use that as a start up/back up disk for the zero'd out 10.5.4?
Because if that was the case then I would be able to get the snow leopard disk out, I hope.

4) Do I have to format one of my hard drives so that I can use it as a time machine and does it still work as a normal external hard drive.
I keep one of my back up drives formatted as a windows drive because a lot of my students use windows laptops. I run MacFUSE & Tuxera NTFS on all my Macs.

Any help would be greatly appreciated!

I'm new to this forum, but I'm looking forward to being a part of this community and hopefully one day I'll be able to help someone else out.
Aug 17, 2010
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Your Mac's Specs
2011 Mac mini and 2010 13" MacBook Pro, iPhone 4 and iPad
1.) Are you using your own iMac Snow Leopard disks (the grey ones)? If so they are specific to that particular Mac model and probably won't work on other models. The retail upgrade SL disk is meant to install on any Intel based Mac though.

2.)If you have an Apple wired mouse hold down the left click on startup of the Mac and it should eject the disk. I haven't tried with a non Apple mouse but it might work the same.

3.)If 2 works you don't have to worry about trying to restore from a Time Machine backup of another Mac.

4.)Time Machine works on Mac OS Extended Journaled so yes you should format the drive for it to work properly. You can always partition the drive though to use part of it for Time Machine and part of it for something else (NTFS or FAT32)
Nov 18, 2011
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thanks a lot!

Yes, they're are the grey disks.

I won't be able to try anything until monday morning.

It has a wired mouse, so I will try that.
Thanks for the time machine info, I'll keep that in mind.

So i'll have to buy snow leopard and Lion?
$60?... I'll get the college to order it haha

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