When it comes to computers, there is nothing like a fresh OS install. Over the years as a Windows user, i used to do a fresh install now and then when the computer started dragging it’s legs. But I’ve never done it on my Mac, a Mac I’ve now filled with crap for two years. And it was now staring to show sign of lagging, and the upgrade to Lion didn’t make it any faster. So I decided to make a clean install of Lion, and start afresh.
The thing you need to make a clean install is a bootable device, a DVD or USB-stick, with the Lion installer on it. When you download Lion from the App Store, you are installing an install Lion package, that you execute when you are ready. In this package, you want to copy the file InstallESD.dmg over to your bootable device. To do so, you must open your Application folder in Finder, right click on it, and choose Show Package Contents. The file is in Contents\SharedSupport-folder. Copy it to your device, and you are ready to go.
When you do the upgrade, Lion deletes the install package. So if you did the upgrade without copying InstallSED.dmg first, you need to re-download the package from App Store. To do so, you must open App Store, and hold down the alt-button while you press the Purchased button. This will list your purchased history, with the option to install the Lion updater again. It seems like you can’t let go of the alt-button before the App Store has shown you the whole list. And after you download it once more, do copy the desired file to you device.
Before you make the clean install, make sure you take backup of everything you need to take backup of. To backup all of your users folders (desktop, documents, downloads, movies, music, pictures, sites) is probably a good tip. In addition it might be a good idea to copy your keychains.
I also made a list of my applications, and made sure I had all my serials stored somewhere safe (in my case Evernote). Apps bought from App Store can be re-installed with no hassle.
So on to the actually install. Pop in your device (I used a DVD) and restart the machine. When it starts to boot, hold down alt. This will give you a list of all your bootable devices. Your current OS X disk, the Lion recovery disk (if you already have Lion installed), any BootCamp disks, and you Lion installer device. It is apparently slower to use a disk than a USB-stick. I used a DVD, and it took some seconds before it showed up next to the others. So when it decides to turn up, double click on it and you you will get the Lion menu.
On the Lion menu, you are here interested in two of the four options. You have Reinstall Lion of course, but before you go there, go in to the Disk Utility option. There you choose your OS partition (where you want to reinstall Lion) and use the erase option. Choose Mac OS Extended (journaled) as your format. When the partition is erased and data free, you go back, and choose Reinstall Lion. And Lion will be installed and you will be guided through the installation steps. You need to enter your App Store user name and password during these steps, so make sure you have them handy.
And so, you’ll hopefully end up with a new and fresh install, where everything works. Or everything crashes and burns. Anyway, it worked for me, and I think it doesn’t lag as much anymore. I could of course be delusional.
What remains is re-installing your software, and copying back your files. Be aware, that any software that came pre-intalled on your Mac when you bought it (like iPhoto, iMovie), are now gone, and you might be in trouble if you have no installation disks with these on.
And if everything goes tits up, you have always internet forums to shout at.
Hi, I’m interested to know whether the clean install of Lion helped you resolve the lagging at all? Thanks.
Yes, it did. It feels like it became a little more responsive. Like a clean install always does.
[...] I did a clean install of OS X Lion some time ago, I hadn’t bothered to reinstall Windows on it yet. I need Windows for some [...]