Recently, I had to reinstall OS X from scratch. I was trying to install windows 7, and boot camp would not give me more than 5GB due to “unmovable files”. Anyway, after many attempts around this (google doesn’t have much in terms of solutions that work), I decided to do what most people say: Do what Apple / Boot Camp is asking you to do… reinstall the OS. So, that’s what I’m doing…
I boot off the snow leopard DVD, start up Disk Utility, and repartition my drive to one large partition (as strongly recommended when using GPT), and try to start the installation. The install button is grayed out! The message right above it states: “Mac OS X cannot startup from this disk”. Some google searches suggested this is because the MBR is somehow messed up (or the installer thinks it is). Several suggestions later (like, resize the partition so something smaller, then save, and immediately resize back to full) don’t seem to work (still getting the same error). So, I figured, since the MBR was messed up, maybe changing the partition type would wipe it out completely. For me, the solution was just that! I changed the partition to MBR via the Options button on the Partition tab. Of course OS X won’t install on MBR, if you don’t believe me try going back to the install screen after creating the new partition. Once the partition is saved, try the installer again (you will see a message that OS X can’t be installed on an MBR partition and it must be repartitioned as GPT in Disk Utility). So, then, change it back to GPT and Apply! Note: Once you create an MBR partition, everything will be grayed out (even the – (minus) and + (plus) buttons.) Don’t panic, just select 1 Partition from the pre-configured configurations pull-down (right above the partition display). Then, go into Options, select GPT, OK, and apply. Now, when you go to the install screen, it won’t complain.
Have fun installing OS X!
Thanks for the over view. This is just bad.
Appreciate the solution! I can try it out.
nice post. thanks
Awesome post!
The very only thing I could find that helped me to sort this problem out. Got my snow leopard installed.
Cheers mate
Glad this helped other people out!
AWESOME! This works great!
Thank you for the awesome post. This is the only thing that worked. Have no idea how this happened to the disk to begin with as i had just write zero’s formatted it and then tried to install.
Thank you for this info. It is still useful for those trying to revert back from Lion to Snow Leopard.
A great solution! This worked flawlessly… Who would have thought?
Great! Thanks. It worked for me.
Thank you so much!!!! spent hours trying to figure it out before this.. THANK YOU!!
holyshit, the only thing that worked for me, love you bro, no homo
Thanks – you solved my problem! =D
Thank you! Strange problem but your post helped!
Just want to thank you for this article. This is what I was searching for (Thanks MSN
THANKS! this worked! you ………are………a…….prophet! ahaha!
You sir are a genius!!! Works absolutely flawlessly!!
Much Help!
Merci Beaucoup!
What can I say that the others before me have not already said. You saved the day! I am passing my old iMac to my son…and after wiping the hard drive I couldn’t get Snow Leopard installed…until I tried your method. Smart idea; quick solution. THANK YOU.
Fantastic….been trying to sort this for ages, thank you
Glad to see this is still helping people out!
you are a genius… for all their splendor macs can sometimes be balky things 😉
Absolutely! 🙂 Glad I could help you out.
No homo man, but I would really like to kiss you right now.