A friend of mine has a desktop Apple computer (I googled Apple computer images and it looks like an iMac). He has Mac OS X version 10.5.8. When we tried to upgrade it the OS reported that there are no updates available.
We googled around to find alternative ways of upgrading the system – 3-4 different clicking paths all leading to the same system update program – but with same outcome.
Finally we tried to download it but we could not find the 10.6 upgrade anywhere. The system does not allow to upgrade to any version higher than 10.6. I'm not able to check it now, but I remember for sure that the computer was bought around 2009-2010, and it is one of these two (1, 2), which should mean that it can be upgraded even up to Maverick.
How to upgrade to the latest OS X version?
Best Answer
Upgrade is a major version change. In your friend's case 10.5 -> 10.6 is a upgrade that costs money. You can buy the DVD from Apple or perhaps used. From there, if the machine meets the requirements for 10.6 the process is to run the installer and replace / upgrade any peripherals and software that no longer work.
From there, all upgrades come electronically from Apple. Again, if the hardware is compatible, you can jump to Mavericks to free (though unlikely for most 10.5 era hardware).
Apple also sells Lion and Mountain Lion from the web store if you need an upgrade that isn't the latest and greatest.
Your first practical step is to go to Apple.com and find in support the article on indentifying your Mac to determine the hardware capabilities before spending any time or money on incompatible upgrades.