I was facing slowness of my MBP after updating to Lion on Snowleapord, it must have happened with so many poeple, in our daily life we download softwares on our Macs and with time to time usage our machines get slow, so the best thing is to have a clean install of OS.
The most frequently mentioned issue is the lack of a bootable DVD, which would allow you to perform clean installs on your Mac, as well as have a bootable OS from which to run Disk Utility.
Apple has attempted to address the need to be able to run Disk Utility by including a recovery drive with OS X Lion. During the Lion installation process, a special recovery disk partition is created. It includes a stripped-down version of Lion that lets you boot your Mac and run a small number of utilities, including Disk Utility. It also lets you re-install Lion, but then you have to download Lion again from Mac App Store and its kind of very lengthy process if you live in that part of world where internet isnt very fast, and file size 3.7GB takes hours to download.
I’m going to show you how to create a bootable version of the OS X Lion installer. I’ll also show you how to use the bootable DVD to erase a hard drive, and then install OS X Lion on it.
Create the Bootable DVD
Creating a bootable version of OS X Lion isn’t that difficult. When you download the OS, the Lion installer is placed in your Applications folder. When you run the downloaded Lion installer, it simply restarts your Mac using the embedded Lion disk image that is buried in the download file. With a little fiddling, you can use the disk image to create your own bootable copy.
If you want to create a bootable copy of the OS X Lion installer, be sure to do so before you install OS X Lion, because the Lion installer delete itself as part of the installation process. If you have already run the OS X Lion installer, you can always download it again by launching the Mac App Store, holding down the option key, and selecting “Purchased” from the icons at the top of the Mac App Store window. You should then be able to download a fresh copy of the OS X Lion installer. Remember to quit the OS X Lion installer as soon as it auto starts, so you can create your bootable copy of Lion.
Burning a Bootable Version of OS X Lion
After downloading Lion from App Store, Open a Finder window and navigate to /Applications/Install Mac OS X Lion. Right-click on the Lion download file, and select “Show Package Contents” from the pop-up menu. Expand the Content folder in the new Finder windows, Open the SharedSupport folder.The Lion DMG (disk image) is in the SharedSupport folder; the file is called InstallESD.dmg, Right-click the InstallESD.dmg file, and select “Copy” from the pop-up menu. Right-click in a blank area of the desktop, and select “Paste Item” from the pop-up menu. Launch Disk Utility, located at /Applications/Utilities. Click the Burn button in the Disk Utility window. Select the file you copied to your desktop as the image to burn, then click the Burn button. Pop a blank DVD into your Mac’s optical drive and click the Burn button again.
The resulting DVD will be a bootable copy of OS X Lion.
Erase and Installation of OS X Lion
This process lets you install Lion on a disk that is empty, or has no pre-existing OS installed on it. In this article, we’re going to use the bootable OS X install DVD you created to install Lion on a disk you will erase as part of the installation process.
Before we begin, remember that you will be erasing one of your volumes to use as the target for the Lion install. You should have a complete, current backup of that drive, because all data on the drive will be lost.
Boot From the OS X Lion Install DVD
1. Insert the Install OS X Lion DVD you create earlier into your Mac’s optical drive.
2. Restart your Mac.
3. As soon as your Mac restarts, hold down the “C” key. This will force your Mac to boot from the DVD. Once you see the Apple logo and the spinning gear, you can release the “C” key. The boot process will take a long time, so be patient.
4. After you complete the boot process, your Mac will display the Mac OS X Utilities window.
5. To erase the target disk for your OS X Lion install, select Disk Utility from the list, and then click Continue.
6. Disk Utility will open and display a list of connected drives. This process can take some time, so be patient.
7. Select the disk you wish to be the target for your OS X Lion install. Remember that we’re going to erase this disk, so if you haven’t performed a current backup of the data on the disk, stop and do it now. If you have a current backup, then you’re ready to proceed. Select the disk you wish to erase. Click the Erase tab.
8. Use the drop-down menu to set the format type to Mac OS Extended (Journaled). Give the disk a name, Click the Erase button.
9. A drop-down sheet will appear, asking you to confirm that you wish to erase the target disk. Click Erase.
10. Disk Utility will erase the drive. Once the erase is complete, you can close Disk Utility by selecting “Quit Disk Utility” from the Disk Utility menu. The Mac OS X Utilities window will reappear.
Install OS X Lion
1. Select Re-install Mac OS X Lion from the list of options, and click Continue.
2. The Mac OS X Lion installer will appear. Click Continue.
3. Accept the OS X Lion license agreement by clicking the Agree button.
4. A drop-down sheet will appear, asking if you agree to the license terms. Click Agree.
5. A list of disks will appear; select the disk you wish to install OS X Lion on. This should be the same disk you erased earlier. Click the Install button.
6. The Lion installer will copy the necessary files to the target disk. The installer may also download necessary components from the Apple web site. In my installation tests, there were some components downloaded and took arround 5 minutes, but this feature may ensure that the installation has the latest updates, and there may not have been any current updates. Once all the necessary files are copied to the target disk, your Mac will restart.
7. After your Mac restarts, the installation process will continue. A progress bar will display, with an estimate of the installation time, which can run from 20 to 30 minutes.
Finish the installation, That’s it, you have installed OS X Lion on a disk you erased to produce a clean install.