[kman42]

We have a mac that has a screwed up installation of OSX and we can't run system preferences (or most other apps). It has OS9, so we would like to switch to OS9 to salvage what we can before reinstalling everything.

What is the key sequence on reboot to switch between osx and os9?

thanks,.
kman

[larkost]

If it is a "New World" Mac (newer than the first iMac, more or less) then simply booting with the option key held down will get you to the firmware's "choose startup disk" screen. If it is older than that you need to boot off a CD and use the "Set Startup Disk" option (system preferences on 8/9 and there is an option somewhere in the MacOS X startup disk... but I don't know where).

[kingskel]

Or just press the "9" key when rebooting. That'll boot you into OS 9.

[Mr. Blur]

Originally posted by larkost:
If it is a "New World" Mac (newer than the first iMac, more or less) then simply booting with the option key held down will get you to the firmware's "choose startup disk" screen.

note that that will only show you bootable *volumes* - so if you have os x and os 9 on the same partition (as most do) then it will only show the default startup os as chosen in the system preferences.

you can start from an os x install cd and set the default to os 9 from there.

also, if you then want to go back to os x, just hold the X key at startup.

[Art Vandelay]

Originally posted by Mr. Blur:
you can start from an os x install cd and set the default to os 9 from there.

FYI... This is only available on the 10.3 Install CD/DVD. Previous versions did not provide a startup disk tool.

[Millennium]

If you're on a New World Mac, then holding down Option will let you choose your OS (as long as they are installed on different partitions). If you're on an Old World mac, then holding down Option will simply boot you into 9; there is no OS chooser functionality on these machines.