Q: Install 10.11.6 El Capitán with 10.6.8 Snow Leopard on old Mac Pro 4,2 multi-boot?
Looking for knowledgeable advice here... I have an old Mac Pro 4,2 (Cheese Grater) that's running 10.6.8 Snow Leopard. This is a wonderful, workhorse machine that has served me tirelessly for many years. It's obviously older and slower now, but works great. I like 10.6.8. If Apple ever refreshes the Mac Pro line (I know, not likely...sigh...), I'll buy one and replace this machine. Until then, I want to make this work.
This machine is a beast, has been upgraded with three 1-TB internal hard drives (it's also got a couple legacy internal HDs of 750 and 500 MB used for storage). I've also got multiple FW800 external drives from 1 to 4 TB plugged in, too. Oodles of storage, obviously, and should be plenty of options for booting into multiple systems.
I'm generally happy with 10.6.8 on this machine, although there are obvious limits to that. I'd like to get one or two newer OSes on it, pick-and-choose between them as needed, but I absolutely want/need to preserve the ability to boot into and run 10.6.8 routinely as my day-to-day OS, at least for now. Maybe I'll warm to one of the others on this machine eventually, but 10.6.8 has got to remain usable, installing a newer OS on other drives can't nerf it.
About a year-and-a-half ago, I took a run at installing 10.10.3 Yosemite on one of the internal drives. That did not work out well. I got Yosemite installed, sniffed around a bit, didn't really like it much, and went to reboot and switch back to 10.6.8 for a bit. That initially was impossible (at least via what I expected would be the same old process I've always used, via System Preferences > Startup Disk). You can read details of that experience here and more here if you're interested. That last attempt to get Yosemite on this machine was a pretty negative experience. Yosemite is still there on one internal HD, but I have not attempted to boot back onto it since then.
Now I'm taking another look at all this. What's driving this now is that I want to update my iPad Mini 3 to iOS 10. But that (updating an iDevice to iOS 10) requires iTunes 12.5.1. And iTunes 12.5.1 requires Mac OS X 10.9.5 or newer - it won't work with 10.6.8. So I'm looking at my options.
Right now, I have three large internal HDs: HD#1, HD#2 and HD#3, each 1 TB.
HD#1 has 10.10.3 Yosemite on it. I booted off this once, and have not gone back since.
HD#2 has 10.6.8 Snow Leopard on it. This is my primary OS and every-day boot drive.
HD#3 has nothing special on it.
Although HD#1 has Yosemite on it, I've only booted off that drive once, and am hesitant to go there again, at least until I can get an easy and reliable path back to rebooting off of HD#2.
I understand I can also get 10.11.6 El Capitán. I was thinking of installing that on HD#3. That sounds like a reasonable option to add, but once again, I want to ensure that doing that won't cause problems switching back to boot off of HD#2 in Snow Leopard (like installing Yosemite on HD#1 did).
What's the best way for me to go about this safely - preserving the option to easily boot into 10.6.8 on HD#2?
Thanks for the help!
Posted on Sep 15, 2016 2:24 PM