iMac (2006) won't let me install system

Drive Preparation

1. Boot from your Leopard Installer DVD. After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from the Utilities menu.

2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Note the SMART status of the drive in DU's status area. If it does not say "Verified" then the drive is failing or has failed and will need replacing. SMART info will not be reported on external drives. Otherwise, click on the Partition tab in the DU main window.

3. Under the Volume Scheme heading set the number of partitions from the drop down menu to one. Click on the Options button, set the partition scheme to GUID then click on the OK button. Set the format type to Mac OS Extended (Journaled.) Click on the Partition button and wait until the process has completed.

4. Select the volume you just created (this is the sub-entry under the drive entry) from the left side list. Click on the Erase tab in the DU main window.

5. Set the format type to Mac OS Extended (Journaled.) Click on the Security button, check the button for Zero Data and click on OK to return to the Erase window.

6. Click on the Erase button. The format process can take up to several hours depending upon the drive size.

7. After the process has completed quit DU and return to the installer. Complete the Leopard installation.

Note that installer discs for specific systems may only work on those systems, so an installer DVD for an iMac released with 10.5.2 installed may not work on the iMac you have which was released in 2006 with a special version of Tiger.

If these are grey-colored discs, they will not work with your iMac. These discs are Mac/machine specific discs and only will work if your have the exact model/serial number range for these to work.

Your iMac year and model take a special version of OS X Tiger 10.4.4 or 10.4.6.

If you are looking to install OS X 10.5 Leopard, you need to locate and purchase the full OEM retail box disc DVD.

These have a colored nebula background with a black "X" on the DVD.

These are very hard and expensive to find, now.

Here are sources for OS X Leopard.

http://store.fastmac.com/product_info.php?cPath=10_5_7&products_id=359

http://www.amazon.com/s/ref=nb_sb_ss_i_5_4?url=search-alias%3Dsoftware&field-key words=os+x+10.5&sprefix=OS+X%2Csoftware%2C247

Good Luck!

MichelPM is spot on. The Early Core Duo's came with a 10.4.4 and you will need either that specific gray Disc 1 & 2 set, a Retail Leopard or Retail Snow Leopard Upgrade Disk to format the new HD and install the OS X.

For example's

iMac Media Set - Includes Mac OS X 10.4.4 Tiger

mac os x leopard retail 10.5 | eBay

mac os x snow leopard retail 10.6 | eBay

I didn't include an update for the OP to update to OS X 10.6 Snow Leopard because I do not think it will run well on the

OP's iMac with only a max. RAM of 2 GB. The OP is better off installing Leopard and staying there.

I think Snow Leopard will just bog down the OP's iMac.

Not true, I have a 17" 1.83 GHz Early Core Duo w/2GB of RAM and Snow Leopard runs great on it.

Actually, Snow Leopard was demonstrably faster than Leopard.

Was that because Snow Leopard was stripped of all the legacy PowerPC code?

I forgot about that.

Possibly, although benchmarks had Snow Leopard running about 20% faster than Leopard depending upon function. So many variables it's often difficult to really know. For me Snow Leopard just seemed so much snappier than Leopard. Rosetta based applications did run slower in emulation than they did natively, so you might be thinking in terms of the comparison of PPC-only applications running in Leopard versus Snow Leopard.