Q: How do I download OS X 10.10 on a Mac running 10.11.4?
I have an iMac currently running OS X 10.11.4. I use this computer primarily with amateur (ham) radio applications. I just learned that a problem I am having with a particular application is because OS X 10.11.__ no longer fully supports a component of that application - but OS X 10.10.__ does.
I would like to be able to download OS X 10.10 to that computer, ideally while retaining the current installation of 10.11.4. I have been informed that if I have both versions, I can select which version loads on boot-up by holding the option key.
So, my questions are
1) from where can I download an authentic version of OS X 10.10. (Ideally this would be somewhere on the Apple website)., and
2) What special steps would I need to take when downloading in order to keep OS X 10.10 and OS X 10.11.4 available on the same iMac?
Thanks,
Brian
iMac, OS X El Capitan (10.11.4)
Posted on Apr 15, 2016 7:18 AM
You can only download Yosemite if you have previously downloaded it or the computer came with that OSX originally.
If the computer came new with El Capitan installed it will not run an earlier OSX.
If you have downloaded Yosemite previously you can re-download it with the Mac App Store app.
If you can find and run Yosemite you will have to either use a separate drive to install Yosemite onto that or split your current drive into two volumes and install Yosemite on one of those. Switching between systems will require a reboot each time.
Posted on Apr 15, 2016 7:36 AM
