Yosemite

When Yosemite first dropped I wasn’t in the mood to be one of the “early adopters”. Normally with a new OS I’d be straight in there but I put off updating from Mavericks and I think I did the right thing. Apparently there were lots of minor problems reported on the discussion forums, not least a problem with dropped WiFi connections. Anyway, I decided I’d wait for a point release and then of course I had my eye problem…

Now that Apple have released a further point release (OS X 10.10.2) which purported amongst other things to fix the WiFi issue I thought I’d update my MacBook Air for starters. Opinion is divided between those who simply update from whatever their existing OS was and those who insist that a clean install followed by a restore of their backed-up data is the only surefire way to a reliable system. I thought I would risk the former and use my backup plan to do a clean install and restore if necessary.

I followed my usual backup method – which is really about ensuring I have a good backup in case of a SNAFU – prior to starting the update. In other words:

  1. Backup to external disk using Time Machine
  2. Create a bootable clone of the entire Macintosh HD partition on an external disk (I use Superduper!).
  3. Test the clone by booting from it and testing the basic functions of OS X.
  4. Verifying the Macintosh HD disk.

No. 4 gave me a couple of disk errors. Nothing serious. Nevertheless I booted the Mac in safe mode (that’s booting it while holding down the CMD and S keys) and running fsck to check and repair the disk:

/sbin/fsck – fy

It found some minor file allocation errors and then returned the message “Macintosh HD appears to be OK” (which is always a good sign). I rebooted it as normal and downloaded the Yosemite installer from the Apple App store.

It pays to have a Plan B, which in my case would be to restore everything to its last Mavericks configuration – I have a backup for that! – but it’s very useful to have a stand-alone copy of the OS X installer on a USB drive. If you have that, you can boot from it and run diagnostics or repairs from there and/or install the OS from scratch if need be. A useful spin-off is that if you have several Macs to update to the new OS, having a copy of the installer on a portable disk saves having to download the large installer image onto each Mac.

Starting with Mavericks, Apple have made it easy to create a bootable copy of the installer. There are other ways of doing it but I think using Apple’s “createinstallmedia” utility is fine. Here’s the method:

  1. When you download the OS X Installer app, it places it in the Applications folder. This method assumes you’ve left it there. (Don’t forget, if you run the installer and update the Mac, the installer app gets deleted from the Applications folder afterwards, so you need to create the USB copy first).
  2. Using Disk Utility, format an 8GB USB drive and give it the label “Untitled”. Leave it connected to a USB port on your Mac.
  3. Open a Terminal window and enter this command:

    sudo /Applications/Install\ OS\ X\ Yosemite.app/Contents/Resources/createinstallmedia –volume /Volumes/Untitled –applicationpath /Applications/Install\ OS\ X\ Yosemite.app –nointeraction

  4. Let it run (takes a while!) and you will be left with a bootable USB disk containing the installer.
  5. To start your Mac from the USB drive, start the Mac whilst holding the Option (alt) key down. Once the Mac starts it will display the list of available bootable drives, select the USB drive from that list.

So, having tested my backups, downloaded the OS X update and created my USB installer, I was ready to undertake the update.

The Yosemite update was very straightforward (as Apple intended) and my Mac was soon up and running. I’ve left iCloud Drive off for the moment until I’m happy that everything is working as it should.

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