Well I popped in my retail disc, click click click, then about a quarter of the way through the install it says something along the lines of "Mac OSX can't be installed - essentials package can not be verified".

Then it tells me to restart and try again. Anyone else have this issue? If it doesn't install, can I go back to 10.4 and still keep all my data? I have 2 hard drives, one has all my work stuff on it, which thankfully isn't the drive im install the OS on. However, I would really like to keep all my emails, MP3's and address book.

Hmm...

Backup everything onto your second drive, format your OS X drive, pop in Leopard and do a clean install, then copy your applications and files back over from your backup drive ?

It's a good idea to run Disk Utility over your HD before doing anything this major to your hard disk. Did you let it verify the DVD first before installing or did you skip that? Once in a while you get a borked DVD.

your not the only one...
Leopard refuses to install on my G5 Dual Core 2.3Ghz.
I'm about to now do a clan install.

I had issues also. I never intended to do a clean install as I had not had the iMac very long and I hadn't done anything or installed anything out of the ordinary. Leopard did not like that one bit. In the end I was reduced to using terminal to copy my user directory over to an external drive and do a clean install after all. Now, hours later, I am still setting up stuff.

Lesson: upgrades arent worth the time.

Well I got it installed.

BUT

Now it just never gets past the grey loading screen, left it for a good hour, just never boots up.

By the way I have a dual 1.8 G5

So is there a way I can copy my home directory over to my second drive somehow?

I'd try starting up in FireWire Target Disk Mode - hold down T I think.

Ricky.