Today, September 30th, marks the release of OS X El Capitan, the latest version (10,11) of OS X. As always I strongly recommend holding off installing it for a little while until any last minute bugs have been discovered and fixed. As always, I expect most Mac users to completely ignore that advice and go ahead anyway! So I have a couple of thoughts for you before you upgrade.
This latest release is a traditional minor upgrade to Yosemite(similar to how Snow Leopard was to Leopard, and Mountain Lion was to Lion). There are plenty of new features added (see here for more info), and minor tweaks to how things are done, but its not a complete reworking. As such, the chances are that it won’t create any significant problems to Mac users on release. But if you use your Mac as a major part of how you make your income, let other people find that out for you – there’s nothing in El Capitan that you can’t wait a couple of weeks for!
If you’re still desperate to go ahead…..please make sure you do a backup of your entire system before performing the upgrade. If the upgrade causes you problems, at least you’ll be able to go backwards and carry on working. I’ve written plenty of stuff about backing up, the most applicable being this one.
And whenever you do the upgrade, I strongly recommend you create installable media for your own use. This will save you downloading the whole 6Gb again should you need to reinstall the new OS on any of your computers. You’ll need to stop the upgrade happening and run a manual process before going ahead, and I did document this for an earlier OS here (in the installation section); I expect the process will be the same but I’ll edit this once I have the public release version downloaded myself (EDIT: the command is slightly different in fact:sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia –volume /Volumes/Untitled –applicationpath /Applications/Install\ OS\ X\ El\ Capitan.app –nointeraction).
Good luck!