Starting up in Yosemite

27 Apr 2015 16:09:23

Michael Corgan

My iMac hard drive is in two (only) partitions. On one I have SnowLeopard, on the other I have Yosemite.
On an external drive I also have Mavericks. Trying to select Yosemite as the start-up, the second partition on my iMac does not show. Mavericks does. What has to be done to allow me to switch between systems?

Re: Starting up in Yosemite

27 Apr 2015 17:27:27

Michael Corgan

I installed Yosemite (again), on an external hard drive. Startup Disk in System Preferences then showeed Yosemite on both drives where it had been installed. Restarting in Snow Leopard, and System Preferences fails to show Yosemite on any drive. So the question is, how can I re-start in Yosemite?

Re: Starting up in Yosemite

27 Apr 2015 18:33:16

Derek Wright

To see all the startup drives hold the alt key down during the power on process. It will then display all the bootable drives/partitions

Re: Starting up in Yosemite

28 Apr 2015 08:13:13

Michael Corgan

Thanks for that Derek. Am I right in thinking that it would then be possible to select the drive you want to boot from?

Re: Starting up in Yosemite

28 Apr 2015 10:38:33

Derek Wright

Yes - select the drive to boot from with the cursor.


If you cannot see the drive that you want to boot from then it would imply that the install of Yosemite did not work correctly.

If you have many bootable partitions it is worthwhile highlighting the preferred partition in the "Startup Disk" in System Preferences. This will save quite a bit of time in the boot up process.