Downgrade Lion to Snow Leopard
1. Boot from your Snow Leopard Installer Disc. After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from the Utilities menu.
2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Note the SMART status of the drive in DU's status area. If it does not say "Verified" then the drive is failing or has failed and will need replacing. SMART info will not be reported on external drives. Otherwise, click on the Partition tab in the DU main window.
3. Under the Volume Scheme heading set the number of partitions from the drop down menu to one. Set the format type to Mac OS Extended (Journaled.) Click on the Options button, set the partition scheme to GUID then click on the OK button. Click on the Partition button and wait until the process has completed.
4. Quit DU and return to the installer. Install Snow Leopard.
This will erase the whole drive so be sure to backup your files if you don't have a backup already. If you have performed a TM backup using Lion be aware that you cannot restore from that backup in Snow Leopard (see below.) I suggest you make a separate backup using Carbon Copy Cloner 3.4.1.
If you have Snow Leopard Time Machine backups, do a full system restore per #14 in Time Machine - Frequently Asked Questions. If you have subsequent backups from Lion, you can restore newer items selectively, via the "Star Wars" display, per #15 there, but be careful; some Snow Leopard apps may not work with the Lion files.
I put the Mac OS X install DVD in my computer and I clicked the Installer and it said You can't use this version of the application Install Mac OS X with this version of Mac OS X you have install Mac OS X 23.1. know what do I do and I want to go back to Leopard?
You need to c boot off the disk
Restoring OS X 10.6
1: Backup your files off the computer to a regular storage drive, not TimeMachine! and disconnect all drives.
2: Hold c boot off the 10.6 install disk, use Disk Utility to Erase the entire internal drive (select the manufactors name and drive size) Use the Erase with Security Option Zero option, your going to be placing a new OS and this is your chance to map off any bad sectors before installing. (more reliable, but takes awhile to complete)
3: When finished use the Partition tab to: Options: GUID, Format: OS X Extended (J) , apply and then quit and install 10.6.
4: Reboot and go through the welcome video, use the same user name as before (different password ok)
5: Software update to 10.6.8, install all your programs from original sources and update.
6: Hook up your storage drive, transfer the contents of your User folders into their respective folders.
Some Exceptions transfering:
Don't transfer iPhoto Library yet, it's a newer version than the older one and won't work.
You need to right click on the 10.7 iPhoto Library and "Show Package Contents" inside is a folder called Originals, copy this folder out and import the original photos into the 10.6 verision of iPhoto so it will place those photo's into the 10.6 version of the iPhoto Library.
The 10.7 iTunes Folder, has a folder inside with your original music files, import those into the 10.6 version of iTunes as well, you'll have to recreate your playlists unfortunatly.
Any other software that likes to trap your originals you also have to perform the same sort of surgery and import them so they work in 10.6's versions of software.
Once you have a nice pristine 10.6.8 drive, take this opportunity to clone it to a blank, powered external drive (or two like me) using the free to use Carbon Copy Cloner. You can hold the option key and boot from this clone.
Note: About TimeMachine
If your TM drive is 10.7, it will have to be erased and reset to image your new 10.6 internal drive.
You can't use a 10.6 TM to restore over a 10.7 with, unless you first erase the 10.7 internal drive.
Apple is all forward and no reverse, to reverse, you need to wipe and fresh install the previous version.
If your Macbook Pro originally came with Snow Leopard installed then re-installing Snow Leopard will not brake your Mac.
BUT !("BUT")! To do so you will need to boot the computer from the original Snow Leopard install DVD disk that came with your system and ERASE/WIPE the hard drive and then do the install.
Erasing and or Wiping the hard drive will delete, REMOVE, all the files on it. That is all Program files, All Music files, All Picture files, All Movie files, and all other personal and operating system files on the hard drive will be completely gone.
So please do a backup to an external drive of all your personal, school, music, picture and movie files you want to keep along with any files stored in the Download folder. Make sure you have the proper files to re-install all your programs. That includes having the Application install DVD that originally came with your system.
Good Luck and best wishes.
Are you sure this is safe because I am only a kid and my Mom will kill me if I brake my Mac?!
If your not familair with backing up or can confidently proceed with the instructions given, then it's best you don't do anything and let someone do it for you.
The worst thing that could occur is you delete yours or others files, which would certainly upset them and you.
Everything else, OS X & programs, can be easily replaced, but not your files. Once those are deleted they are gone.
One more thing will I have to do the setup all over again like create my account when I first turned on my Mac
There is a few things to do before returning your files from the backup drive to the 10.6 new setup.
1: Right click on the 10.7 version of the iPhotoLibrary and copy out the folder called Originals, this contains all your photo's. Import them into the 10.6 version of iPhoto.
2: Copy the inside 10.7 iTunes folder that contains all your music only and import them into the 10.6 iTunes. Then create new playlists like a new user again.
Its because your going backwards that you need to get your original files.
A 10.6 iTunes or iPhoto can't work with 10.7 files it creates, so you have to extract your original music and pictures and reimport them again.
Get your original Snow Leopard install DVD and put it in the DVD drive. Reboot the computer and hold down the C key. That should tell the computer to boot off of the DVD drive. If that doesn't happen then reboot and hold down the option key. That will bring up a screen that has the drives you can boot the computer from. Select the SL DVD to boot from.
Once the computer has booted from the SL install DVD open Disk Utility and select the DRIVE (not just the volume) and then the Partition tab. From the drop down partition list select One Partition, Give it a name (Macintosh HD), make the format Mac Extended (Journaled) and then click the Option button and make sure the Partition Table is set to GUID. Close the option window and click the Apply button. Once that is done proceed with the install of Snow Leopard.