We now have
official word that Mac OS X Lion is launching "tomorrow" (likely tonight Australian time).
A big decision to make every time a new OS comes out is clean install vs upgrade install.
Pros for Clean Install
Crud left lying around: While Mac OS X may not be plagued with the dreaded Windows registry, that does not mean that application developers don't leave files all over your system that don't go away when you remove the app in question (although
AppZapper can help with that.
A fresh start: I have over 100 applications on my computer. I doubt I use all of them. A clean install lets me just add the applications back as I need them.
Pros for Upgrade Install
Really easy: No chasing up preference files. No going to use App X in a week's time and not finding it, having to download a 100MB+ file from the Internet and then finding my serial number for it.
Really quick: You will probably be all done in about an hour, start to finish.
On Time Machine
I love Time Machine. Between my wife and my laptops we've had a few hard drive failures and a Time Machine restore makes it as though nothing happened at all. In this context, though, that means that all those left over preference files and caches are also restored, quickly turning your freshly installed OS into a one or two year old system.
When you go to restore from Time Machine using the Migration Assistant you have the option of migrating the following files:
- Users
- Applications
- Settings
- Other files and folders
Now, you could only restore the Users option, which would mean that your Applications, Settings and the
Local Library will not be restored. However, not only does this mean that your Local Library might be lost with important data before you realise it (due to Time Machine deleting older backups), but also your
User Library, which stores a lot of application data,
will be restored.
My Solution (use at your own risk)
I have come up with a solution that I think provides you with the benefits of a clean install, but reduces the risk of losing any of your important data.
Here's the process:
1. Back up with Time Machine.
But you were doing this already, right?
2. Do a static back up of your Applications and Libraries.
Create a folder on your external harddrive called 'Static Backup'.
Inside that folder create folders called 'Applications', 'Library' and 'Users'.
Inside 'Users' create one folder for each of the Users on your computer.
Inside each of those user folders create a folder called 'Library'.
Copy and paste the following into the AppleScript Editor:
set myPassword to "password"
set myHarddrive to "harddrive"
do shell script "rsync -a --delete /Applications/ /Volumes/" & myHarddrive & "/StaticBackup/Applications/" password myPassword with administrator privileges
do shell script "rsync -a --delete /Library/ /Volumes/" & myHarddrive & "/StaticBackup/Library/" password myPassword with administrator privileges
set myUsername to "username"
do shell script "rsync -a --delete /Users/" & myUsername & "/Library/ /Volumes/" & myHarddrive & "/StaticBackup/Users/" & myUsername & "/Library/" password myPassword with administrator privileges
Replace password with your admin password. (Don't save the file with your password entered, but set back to password before saving.)
Replace harddrive with the name of your external hard drive.
Make copies of the last two lines for each of the users on your system. Set username for each accordingly.
Run the script.
You will now have a back up of your Applications, your Local Library and all of your User Libraries.
You can run this script at any time and then again just before doing the OS install and it will just update the files already backed up.
3. Install the OS
Do one final Time Machine backup.
Do the fresh install.
When the system asks if you would like to migrate data from Time Machine, say no.
Create the users from your old system.
4. Restore your user data
Once the OS install has finished, enter Time Machine and browse to your user directory.
Select all the folders, except for the Library, and select Restore.
Repeat for each user on the system.
5. That's it (for now)
You now have a completely clean system, but still have all of your user data, including iTunes and iPhoto libraries.
If you install an application and realise that some important data is missing, there is a 99% chance you will find it in your static backup.
After some time (maybe six months) you can probably just delete your static backup.
Conclusion
It certainly does not have the simplicity of a Time Machine restore, but a new version of OS X only comes out less than once per year. I think it is probably worth it for that fresh new car smell.
Oh, yeah, and don't forget to check
Roaring Apps to see if your mission critical apps are stable in Lion.