How to prepare your Mac for OS X 10.7 Lion

OS X Lion has just been released as a Golden Master build to developers, and provided all goes according to plan it should be slated for public release sometime later this month. Unlike with prior releases of OS X, Apple has taken a few different turns with Lion, especially in how it will be distributed to users. In addition, the system requirements for the upgrade are going to be a bit more constrained than in the past, so here is how to best prepare for the upgrade.

The first thing to do is ensure your system will run it. Any Mac that runs Snow Leopard should be able to run Lion, with the exception of the very first Intel Macs that shipped with Core Duo and Core Solo processors. These include the following systems:

1. iMac (Early 2006 and Mid 2006)
2. MacBook Pro 15-inch and 17-inch (Early 2006)
3. MacBook (Early 2006)
4. Mac Mini (Early 2006 and Late 2006)

If you have purchased your system in 2007 or later, then you should be good to go for upgrading to OS X Lion; however, you can check for the processor type on your system by going to the Apple menu, selecting "About This Mac," and then looking at the Processor section. If you see Core 2 Duo, Core i3, Core i5, Core i7, or Xeon in the processor name, then you should be good to go. If you only see Core Duo (without the number 2 in it), Core Solo, or any form of PowerPC, then you will not be able to run Lion.

Beyond the CPU requirements for Lion, you may also consider upgrading your RAM to at least 2GB, but preferably 4GB if possible. Macs in around 2007 to 2008 shipped with between 512MB and 2GB RAM, and Lion will require at least 2GB of memory to run adequately. You can see how much RAM is installed by going to the same About This Mac window, but consult your Mac's manual to see how much RAM you can install; some models can only upgrade to a maximum of 2GB of RAM.

Upgrading current installations

If you have a current OS X installation, unlike previous releases of OS X, Lion will not be able to upgrade from all of them; its requirement for the latest version of the Apple Store application will require you to have the latest OS X 10.6.8 version installed. This means that if you are running any version of Tiger or Leopard on an Intel Mac and wish to upgrade, then you must first purchase and install Snow Leopard, and then upgrade it.

Apple still provides OS X Snow Leopard upgrade kits for people running Tiger and Leopard, so if you have not yet upgraded to Snow Leopard and are considering the move to Lion, then now might be a good time to purchase a Snow Leopard upgrade; however, after installing it you should consider the following before immediately moving to Lion:

1. Check for PowerPC use
   Snow Leopard and prior versions of OS X have included the "Rosetta" translator that allowed older PowerPC code to run on Intel Macs; however, this will no longer be available in Lion so be sure to check for any programs you use that are PowerPC-based, and upgrade them, find alternatives, or simply understand that they will no longer run in Lion. You can check for PowerPC applications on your system by using the System Profiler utility (see how to do this here).

2. Clear up any existing problems
   If your system is running slowly or having stability issues, you might consider addressing these before upgrading. A basic step you can take is to run a general maintenance routine, but in addition you might consider uninstalling system add-ons that you don't use, and otherwise slimming down your system. Any program that persistently runs in the background (system monitors, notification tools, and communications tools, etc.) may cause problems if they are not fully compatible with Lion.

3. Upgrade your applications
   Check for updates to any software you have running on your system, and install them if they are available. Developers will likely be releasing compatibility tweaks and updates to their software to ensure that they run in Lion, so if you use third-party utilities and programs, be sure to regularly check for updates to them in the upcoming weeks before and after Lion is released.

4. Options for running OS X 10.6.8
   Eventual upgrade to OS X 10.6.8 will be necessary in order to use its version of the App Store; however, it is not necessary to upgrade to it until you are immediately ready to install Lion. Currently people are having several prominent issues with OS X 10.6.8 that may impede on your workflow, so one option you can consider is to run in OS X 10.6.7 for now and ensure the system is running smoothly. Then when Lion is available and you are ready to upgrade, you can install the OS X 10.6.8 update followed immediately by installing Lion.

Performing clean installs

One of the most common questions surrounding Lion is whether or not users will have the option for performing a clean install on a freshly partitioned and formatted hard drive. This has been an appealing option in past versions of OS X because it gives users an excuse and a means to start fresh and to "clean house," so to speak.

Unfortunately Apple has released little information about the options for this, leaving people confused about whether or not if at all they will either be able to burn a boot disc of the installation media or create one out of a secondary hard drive. Recent comments from Steve Jobs suggest that a clean install will not be possible, and instead offered the option for users to use older Snow Leopard installation discs to wipe their drives, install the OS, and then upgrade to Lion. Unfortunately this will require a number of additional steps to the "clean install" process, including the setting up Snow Leopard and subsequent updates to version 10.6.8, establishing an App Store account, and then a downloading and installing Lion.

While these added steps and requirement for using an older version of the OS is a bit of a frustration (especially since an upgrade from OS X 10.6.8 to OS X 10.7 is technically not a clean install), it may not be necessary for most people.

Recently discussion of OS X Lion has surrounded a Recovery Partition that Lion apparently sets up on the boot drive, and whether or not that will allow for a clean setup of the OS. Apple has not officially mentioned the recovery partition option in Lion yet, but if such a partition supports a reinstall of the OS, then this coupled with Steve Jobs' recommendation would ultimately allow you to set up Lion from scratch. Here is the process one would have to take:

1. Boot to a Snow Leopard disc, partition and format the drive, and install Snow Leopard.
2. Upgrade Snow Leopard to version 10.6.8
3. Using the App Store, install Lion.

At this point the Lion installation is an upgrade installation that may not be desired; however, it will have freshly created the Lion recovery partition, so you can then continue:

4. Boot to the recovery partition (holding the Option key after hearing the boot chimes, and selecting the disk)
5. Erase the volume with OS X Lion on it
6. Install Lion freshly from the recovery partition.

When this process is complete, the Lion installation will be a fresh and clean one. It is unfortunate that you would need to use a Snow Leopard disc for this, but you could at least be able to set up a clean installation on a freshly formatted hard drive.

It is possible that Apple will offer an option to create a separate boot disc, thumb drive, or hard drive partition on a secondary device, but because Apple is appears to be shying away from alternate boot media and has not mentioned any alternatives, we highly recommend you retain your Snow Leopard installation disc for any Mac that you are upgrading.

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