So you’ve upgraded to Lion, got all excited, but then found that important applications like Microsoft Office and Adobe Flash aren’t working properly. We did try and warn you but don’t worry – bugs like this are normal with a new OS release and updates will surely be released in the next few weeks and months to fix them. However, if Lion is making your life hell, you can always downgrade back to Snow Leopard in a few simple steps.
1. Backup your files to an external drive
Make sure you’ve got a backup of your files using a tool such as Time Machine, SuperDuper or Carbon Copy Cloner. If the last time you backed-up on Time Machine was with Snow Leopard, your life will be a bit easier. If you’ve overwirtten it since then with a Lion backup however, you’ll find that you can’t restore a Lion Time Machine backup in Snow Leopard because of comptability problems. In this case, just drag your user folder (Macintosh HD/Users) from Lion into an external drive and then you can just drag it back into Snow Leopard. Note that it’s important to backup to an external drive because shortly, you’ll be wiping your hard drive.
2. Boot from a Snow Leopard Disk
Insert the Snow Leopard disk. Shut-down your Mac, switch it back on and hold down the “Option” key and select Snow Leopard.
3. Erase your hard drive
Use Disk Utility to erase your Hard Drive completely. This is to prevent any conflict that may occur by installing Snow Leopard over Lion.
4. Install Snow Leopard
Using the OS X Installer, install Snow Leopard onto your new clean hard drive.
5. Restore your files and folders from your backup drive
Restart your Mac, connect your backup external hard drive and use your backup program to restore your files and folders to Snow Leopard.
This is the most simple method and the last step will depend on which program you used to backup your files. Note that even though this is a clean install, you may experience issues with some files, folders and applications if you modified or updated them in Lion.