(updated Sun 3 April 2016)
Yesterday I upgraded my primary computer (a 2012 Mac Mini) to El Capitan (OS X 10.11).
It’s normal for me to wait 6 months or so for the .3 or .4 OS X release, to allow Apple to fix hardware, networking, performance problems or random bugs and – crucially – for other developers to do the same with their applications (by no means everyone is actively testing software on the beta versions.) I’d recommend this to others.
- Backup first (obviously.)
- I recovered around 40GB of free space after installation (and 17GB on a Macbook Air upgraded soon after.)
- performance is generally snappier (the CPU graph in Activity Monitor looks flatter when the system is idle, also considerable improvements when previewing files – not just PDFs but video as well)
- performance will degrade considerably immediately after installation (less so on an SSD, but the Mac Mini’s HDD + Fusion Drive suffered a lot) as Spotlight reindexes everything (you’ll see sustained high disk IO and high CPU from md5 and associated processes.) If there is more than one user of the computer, this will happen the first time each user logs in, as each has a separate Spotlight database. If you use Dropbox, temporarily quitting that will help it complete faster. Keep Activity Monitor open and once indexing has finished, disk IO will return to zero.
- I recommend a clean restart after that to check everything is ok.
- You’ll need to upgrade the usual things, e.g. XCode, any Text to Speech voices you have installed.
- Homebrew requires a change of ownership for /usr/local/ – see discussion on Stack Exchange – to the best of my knowledge chown -R is perfectly safe, but you certainly shouldn’t start messing around disabling SIP.
- SuperDuper – a program that does disk backups and cloning – requires you delete and recreate any existing scheduled backups, otherwise they won’t run. More info
- Expect to do one large Time Machine backup afterwards (again, this was smaller on the Macbook Air.)
- I only had one program that was incompatible, a version of GPG (encryption).
- If you still have Photoshop CS4, it needs the old version of Java. This is painless – on attempting to run it a Dialog Box informs you of this, the More Info button links to an Apple support page with a direct download to the file. You just install it and it works straight away.
- No issues at all with PhpStorm (Jetbrains had display problems last year because of java bugs.)
Previously, Apple developed two-step authentication, with El Capitan they added two-factor authentication. The former is still supported, the latter is more secure – “It uses different methods to trust devices and deliver verification codes” – but it requires first turning 2-step off, adding security questions (note your answers are max 32 characters) and then setting up 2-factor on an iOS device (which’ll discard the security questions you just created.) Instructions (9to5mac)
Note that, given the current Apple/US government iPhone case, if you can’t get in with two-factor there is a recovery process (unlike if you lose your FileVault recovery key, say) but it’s not immediate. The KB article refers to a confirmation email to your registered account, possibly being required to confirm credit card details etc.