Snow Leopard reinstall from USB

[CyrusOz]

I have an old Imac that has some issues and i've decided to reinstall SL from a disc image on USB (the same one I used once before) and for some reason when I try to restart and hold down the option key, it will bring up the HD and the USB with the SL dmg file but as the reinstall is just about to start i get the error message saying that it can't be installed on the MAC HD.... i'm not sure what is going wrong.

Can anybody please help? I don't have the install discs and that's why I'm going from the USB. FWIW it has all of the SL updates up to Yosemite, not sure if that is an issue.

Any assistance at all is greatly appreciated.

 

[Bruno09]

Hi,

you can not "downgrade" from Yosemite to Snow Leopard without wiping the disc, hence the error message you got.

So if you actually want to install Snow Leopard, you must erase the disc (all data will be lost) : boot up from the USB then go to the menu bar / Utilities / Disk Utility, select the WHOLE disc, the one at the very top of the list with a brand name (Hitachi, Toshiba, Samsung...) and erase it (Mac OS X journaled extended format).

Now quit Disk Utility and install.

Of course you must save any data you want to keep before erasing the disc.

 

[CyrusOz]

Ok thanks for that information Bruno09. Just to clarify, the only way to do a clean install of the OS is to do what you said, is that correct? The mac has so many issues that i really need to do a clean install but i'm guessing if i just do a reinstall of Yosemite it'll retain all of the same/existing problems.

I'm really looking for the easiest (quickest) way of cleaning up the mac (everything is backed up) but i don't care what version of OS it's running, as long as I can update it to newer versions when i'm ready later.

Thanks again for your help and any clarification you can offer.

 

[Bruno09]

Ok thanks for that information Bruno09. Just to clarify, the only way to do a clean install of the OS is to do what you said, is that correct?

Yes it's correct.

After you have installed Snow Leopard, run Software Update to get all the available updates for Snow Leopard.

 

[CyrusOz]

Ok thanks.. one quick question. When you say 'boot up from the USB' how do i do that? Do i have to change some preferences so that happens or is it just a matter of restarting and holding down certain keys?

 

[Bruno09]

Restart and hold down the Option key, select the USB drive, hit Enter.

 

[CyrusOz]

ok thanks, but thats what I did yesterday and it goes through what language etc and then i have to 'accept' but then it gets to this screen that ive attached and i can't proceed any further - same as before.

[url=http://postimg.org/image/nfhcbhybb/] [/URL]

Any more suggestions please?

 

[Bruno09]

What model of iMac exactly ?

How did you make the USB installer ?

Did you already manage to install SL on THIS Mac with THIS USB installer ?

Did you actually erase the disc ? I would say you did not, hence the "At least 197.23 free", which is not normal in my opinion.

You also may need to re-partition the disc, one partition Mac OS X extended journaled, GUID partition scheme. (see Options in Disk utility / Partition).

 

[CyrusOz]

What model of iMac exactly ?

How did you make the USB installer ?

Did you already manage to install SL on THIS Mac with THIS USB installer ?

Did you actually erase the disc ? I would say you did not, hence the "At least 197.23 free", which is not normal in my opinion.

I did this USB installer by following some youtube tutorials on how to create it using utility.

I used the same process to install SL on this mac years ago but not with this USB.

I have not yet erased the disc... for some reason i misunderstood what you wrote earlier. So this will only work once i erase the HD first.. sorry about that... i'm not sure why i'm having so much trouble understanding simple instructions today.

I'll erase my HD/DIsc and then try again.. unless ive got that bit wrong too

 

[Bruno09]

For your installer to work, it must be compatible with this Mac, hence my question.

Example : imagine you make a bootable installer from a retail 10.6.3 Snow Leopard sold by Apple and try to install on a Mid 2011 iMac that originally shipped with Snow Leopard ---> this would NOT work because that model of Mac originally shipped with a later version of SL : 10.6.6 or 10.6.7.

And again, you need to erase the (whole) disc to be able to install Snow Leopard.

Do this just to be sure : Disk Utility / Partition : 1 partition
Mac OS X extended journaled
Options : make sure GUID is selected
Apply.

 

[CyrusOz]

For your installer to work, it must be compatible with this Mac, hence my question.

Example : imagine you make a bootable installer from a retail 10.6.3 Snow Leopard sold by Apple and try to install on a Mid 2011 iMac that originally shipped with Snow Leopard ---> this would NOT work because that model of Mac originally shipped with a later version of SL : 10.6.6 or 10.6.7.

And again, you need to erase the (whole) disc to be able to install Snow Leopard.

Do this just to be sure : Disk Utility / Partition : 1 partition
Mac OS X extended journaled
Options : make sure GUID is selected
Apply.

Yes i understand what you're saying and that makes sense.. thanks for persevering with me. Your instructions are exactly how I did the USB but to be certain I did it again anyway. The dmg file I am using is called snowleopard_10a432_userdvd.dmg which seems to be a common file name so I'm guessing it's nothing weird.

So if I erase my hard drive through disc utility, then i run the USB installer that should work.. is that correct?

 

[Bruno09]

Looks like the "snowleopard_10a432_userdvd.dmg" is a 10.6 version, so it will only work on a Mid 2009 or older iMac.

(Late 2009 models shipped with 10.6.1, therefore 10.6 can not be installed).

To erase the disk, you must boot up from the USB installer and use its Disk Utility (menu bar / Utilities) so that you can wipe the whole internal disc as explained above.

 

[CyrusOz]

Looks like the "snowleopard_10a432_userdvd.dmg" is a 10.6 version, so it will only work on a Mid 2009 or older iMac.

(Late 2009 models shipped with 10.6.1, therefore 10.6 can not be installed).

To erase the disk, you must boot up from the USB installer and use its Disk Utility (menu bar / Utilities) so that you can wipe the whole internal disc as explained above.

Ok Well this is my old mac i'm trying to do this on. According to "About this Mac" it's an early 2009 model.... so this version of SL i have should work right?

 

[Bruno09]

The Early 2009 iMac originally shipped with Leopard 10.5.6, so yes it should work.

 

[CyrusOz]

Cool, thanks for for hanging in there with me. I appreciate your feedback and support. I need to get this mac sorted so my daughter can start using it but i've had too much happening lately to sit down and do it properly.. i plan to do this today though.

Thanks again

 

[CyrusOz]

It worked, thanks very much mate. Now I just have to figure out what I am able to upgrade to as I know my daughter will HAVE to be up to date lol