Cannot change Hard Drive to GUID

If you could supply a screenshot of your disk utility open with the HD showing it would help.

 

I am having this exact same problem. I upgraded to the Seagate 500 GB HD and tried doing some upgrades today to find out my partition scheme is the Apple Partition and not GUID.

I cannot erase or partition, the buttons are greyed out and simply cannot be done. I tried booting from the CD but I cannot because it is the Apple partition sheme.

This is like a catch 22, how do I erase this and reinstall to GUID?

 

What cd did you try to boot from? You should be able to boot from the CD no matter what the partition scheme of the HD is.

 

erase all partitions (second next to first aid) on the Harddrive level in diskutility

then recreate a new one should allow you to set the optiones you want

 

I had exactly the same problem. If you have a TimeMachine backup this is what works to change to GUID partition without losing anything.

1. Boot from the Snow Leopard Install DVD by holding the C key while booting
2. Instead of installing Snow Leopard, choose Utilities > Disk Utility from the menu and choose tab Partition.
3. Set 1 or more partitions and choose GUID. This wil erase everything and create new partition(s). You will get everything back later from your Time Machine backup.
4. Now Install Snow Leopard
5. After installing you get to a screen that says "Do You Already Own a Mac?". Choose the option to transfer information from a Time Machine backup (make sure the HD that contains the TM backup is connected). Choose the TM backup and presto, your original files and settings will be put back.

 

u cant just go to the partition tab, theres more to it. click on the thing that has selections, like when u click it a list comes up, ok so its called Volume Scheme, the default one should be current, click on that, then if u are just partitioning it for 1 os, or if u are adding snow leopard to another half of ur drive, for upgrading click 1 partition, for both leopard and sl, click 2 partition, then click options, then click the guid thing, then you should be all set.

 

As pcs are junk said -

The "Options..." button will be grayed out unless you change the Volume Scheme from Current to a specific number of partitions (probably 1).