We’ll say it upfront, right at the start of this review, that everyone should definitely upgrade their Macs to Leopard. It’s simply the best version of OS X yet, and there’s no reason we’ve found not to upgrade, provided your Mac meets the minimum system requirements. Leopard isn’t a Windows Vista-style bloatware addition that nobody actually wants – the new features in Leopard are genuinely worth the asking price.

Now we’ve come clean about our love for Leopard we can get down to what we did and didn’t like. For instance, the installation wasn’t as smooth as we’d have hoped for. For this review we installed Leopard on a variety of Macs we had lying around the office and the results were mixed.

Installation

There are basically two main ways to install OS X – you either perform an Upgrade (which is the default setting) or a Clean Install. The Clean Install option wipes your hard drive completely and installs Leopard on the now-empty drive. The Upgrade option installs Leopard on top of your existing version of OS X, so you don’t lose any of the programs you’ve installed, or your data. You can also choose to Archive & Install, creating a new, fresh system and moving the information from your old one to a folder on your hard disk, from which you can copy out any support files you find you need.

The gorgeous new 2.4GHz Intel Core 2 Duo iMac with 1GB of RAM sitting on our reviews bench performed an Upgrade installation without a hitch, as did the 2GHz Intel Core Duo MacBook Pro. In fact, things were looking promising for the Upgrade option until we tried it on a slightly older system – a Power Mac with a 1.25GHz PowerPC G4 processor. The upgrade informed us that it had successfully completed but after the reboot all we got was a blue screen and we could proceed no further.

In the end we had to boot from the Leopard CD and perform a clean install, losing any data on our Mac that wasn’t backed up. An Apple Knowledge Base article acknowledges this fault can occur on systems where Unsanity’s Application Enhancer has been installed. However, we’re pretty sure we haven’t installed that on our test Mac, and the blue screen problems reported on the internet seem to be more widespread than can be accounted for by that one program. In any event, a clean install solved the problem.

Our final test was on a 13-inch 2.0GHz Intel Core 2 Duo MacBook, and here we bumped into another Leopard problem that stopped the installation in its tracks. At the point in the installation where you choose which hard drive to install Leopard on, a red exclamation mark appeared on our hard drive, preventing us from installing.

It turns out you can’t install Leopard onto a volume that isn’t partitioned using a GUID Partition Table. The MacBook uses Apple Partition Map, which was compatible with Tiger, but not Leopard. This meant our only option was a clean install, partitioning as a GUID Partition Table using Disk Utility first.

In summary then, with Leopard we encountered a few installation problems that we’d never had before with OS X. While Tiger was rock solid when performing an Upgrade install, it seems Leopard is much happier with the Clean Install option, so we’d recommend you back up your data first then do a clean install of Leopard, if you want to ensure a trouble-free set-up.