Yesterday I needed to upgrade my Mac Mini, which I use as core component of my hi-fi, to MacOSX 10.4 (Tiger).

Sure enough the upgrade process was simple. Everything installed fine, with the installer detecting my bluetooth mouse and keyboard. I had no need to move the Mac Mini, no need to replace any connections to my plasma display, no need for other keyboards and mice.

However, that was the second take.

The first take went badly. When I first attempted to upgrade, I stuck the operating system DVD into the Mac Mini and rebooted. Got the grey screen, then some weird video error, and the system crashed. My mate Mark says I should be fair and balanced about this. (Or words to that effect, but not in the Fox News meaning of the phrase.) After about 20 minutes of plugging of different monitors, mice and keyboards, the penny dropped.

I force-ejected the DVD by keeping the mouse button pressed down when booting the Mac. And looked: MacOSX Panther. Ah.

So, some lessons:

• never upgrade your operating system (OS) when you’re in a rush
• never pick up the OS box in a darkened office, ‘cos they’ll all look the same
• bin unwanted old versions of OS

And, one lesson for Apple: please don’t cause a system crash if the OS is incompatible. Why was it incompatible? Well, the Mac Mini was launched after Panther was released – this is why when you come to reinstalling an OS that came with your Mac you should always use the installation disks that came with your Mac. During the installation of an OS, the DVD is the OS and so it cannot always be compatible with versions of hardware that came after it.