Downgrading 10.5.8 => 10.4.11

Suggestion. Keep Leopard on your current hard drive. Install a second hard drive & then install Tiger/classic on it. Use the Startup Manager (depress Option key at startup) to select the Tiger or Leopard drive.

 Cheers, Tom 😉

Unless copying OS9 in the finder is easy stuff - eg from my dying PB G4 where I know there is a functioning Classic OS. Is it possible just to copy over Classic OS?

YES, that works just dandy for Classic use! 🙂

Why not physically switch the hard drives within the G5 so the Leopard installation becomes the secondary?

I have never owned a Power Mac G5 and thus do not know the level of difficulty involved in my question, this was a trivial exercise with the Power Mac G4s. If you are able to physically rearrange the order of your drives, you wouldn't have to go through the exercise of two installations. You'd only have to deal with just the Tiger/Classic.

Mechanically there wouldn't have been any issues.

The issues might have been with application versions, especially if you were trying to migrate preference settings and the like from a newer version of an application to an older. I don't think there is a list of applications that can be downgraded and you'd have to be very specific in asking in case somebody else here had tried, or you'd just have to experiment. For example, would your Mail addressbook from Leopard work in Tiger? I don't know.

You would have had to basically erase the drive and reinstall everything. There isn't a "downgrade and install" like an "upgrade and install". Then you'd have to copy things back on and hope app. versions didn't alter radically.

Really depends how old your PowerMac G5 is, what you can do.
The serial number from Apple menu -> About This Mac -> More Info under the Hardware section will tell you the age of the Mac. It consists in the beginning of two alphanumeric characters for the manufacturing site, one number for the last digit of the year, and two numbers for the week of the year. I.e.

K8515, BG515 = the 15th week of 2005, or April 9, 2005. So we'll use the example above, which may not be an actual manufacturing site example, but the appearance will be similar.

PowerMac G5s released on or before:
K8514 and smaller - April 8th 2005 - Can use any * disk that doesn't say Update, DropIn, or OEM. Note this will not include iLife.

K8515 - April 8th through 29 April 2005 can use the same as above and the Update and DropIn discs. Note this will not include iLife.

K8517 - April 29th through October 30, 2005 can use the 10.4.3 and 10.4.6 retail installer disk that looks like the image above to install 10.4. Note, this will not include iLife.

K8544 - October 31, 2005 to April 2, 2006 can use the 10.4.6 retail disk that looks like the image above. Note, this will not include iLife.

K8614 - April 3, 2006 and later PowerMac G5s must use the PowerMac G5 installer discs that came with them to install 10.4 on the machine.

All PowerMac G5s, to restore Classic, must use these restore directions from their original installer discs to install Classic:

http://docs.info.apple.com/article.html?artnum=61802

you can copy over fonts, and known compatible extensions and control panels with the PowerMac G5, but they others may not work as well with it. Some drivers don't work with Classic either. You won't be able to boot 10.4 on your PowerMac G5. See my FAQ* on migrating to Mac OS X:

http://www.macmaps.com/macosxnative.html

To determine the age of your PowerMac G5,

- * Links to my pages may give me compensation.

Message was edited by: a brody

Message was edited by: a brody

That's the 9th week of 2004. Meaning it can install any retail 10.4 which looks like *, does not say Upgrade or OEM, or DropIn.

- * Links to my pages may give me compensation.