2007 iMac won't recognise boot USB drives...

[Nige321]

I have a mid 2007 iMac.

I've created Mountain Lion and Mavericks USB boot drives on different USB sticks and neither will boot the iMac.

They WILL boot my 2013 iMac and my 2010 MacBook Pro...

The drives show up in the Contol Panel Startup Disk panel, but are not available when I boot using the Alt key...

Any thoughts?

Anyone!

Chhers

Nige

 

[hfg]

Try a PRAM reset, let it cycle through the "chime" 2 or three times before releasing the keys. Then try the boot manager again. PRAM reset seems to fix a lot of "boot problems".

 

[TyPod]

PRAM is a good idea. Have you tried other USB ports on the iMac? I've re-installed ML on several 2007's using a USB drive with no problems.

 

[Nige321]

Mmmm

Tried the PRAM reset (Twice) with no luck.
ALso tried different USB ports.

There seems to be occasional posts about this all over the net, with various machines and versions of OSX.

Maybe try a third different USB drive...?

 

[stroked]

Does your 2007 iMac have 64 bit EFI?

 

[MyMac1976]

Did you reintroduce them to one another? I know I don't recognize people or things I don't see often.

 

[Nige321]

Does your 2007 iMac have 64 bit EFI?

Apple iMac "Core 2 Duo" 2.4 24-Inch (Al) Specs
Identifiers: Mid-2007 - 24" - MA878LL - iMac7,1

Did you reintroduce them to one another? I know I don't recognize people or things I don't see often.

Well that's a help...

 

[Nige321]

Does your 2007 iMac have 64 bit EFI?

What difference would that make?

 

[stroked]

What difference would that make?

All the difference. Google it.

 

[Nige321]

Does your 2007 iMac have 64 bit EFI?

It must have, it's running Mountain Lion... Simply can't boot from a USB drive with ML on it... It can see it, it appears in the Startup Disk pane, but it doesn't boot...

 

[paukivbashne]

I'm experiencing (almost) same issue with latest 2013 iMac
tried to install ML thru my usb stick that still works on everything except iMacs!!! ( i tried on 2012 model as well)
it showed up in boot menu as "efi boot" but when i go for it it shows me crossed circle
don't know what the hell does this means so i went with internet recovery (cmd+r) and installed it over internet