Reformat and reinstall

Question

When I first got my Mac, I partitioned the startup drive. Now I'm running out of space and want to reformat as a single drive.
My plan:
-Back up the entire boot partition to an external drive
-Reformat the boot drive
-Re-install OSX3.9
-Copy back and/or reinstall all software, libraries, folders, etc.
Obviously I want the reformatted drive to be as identical to the current one as possible.
Are there any pitfalls to this proceedure?
Will I lose valuable data/settings in the process?
Any precautions I should take?
Is there any utility software that may make this process simpler?
Thanks to all for any insight!
--Barry
G4 1.25 mirror doors   Mac OS X (10.3.9)  

Answer 1

If you have no problems with your current system other than hard drive space, then you might do the following:
First, boot from your OS X Installer. Be sure to use the installer for the version of OS X you have installed. After the installer loads select Disk Utility from the Installer menu (or Utilities menu if using Tiger.) After DU loads select your OS X volume from the list on the left, click on the First Aid tab, then click on the Repair Disk button. If DU reports any errors that have been fixed, then re-run Repair Disk until no errors are reported. If no errors are reported click on the Repair Permissions button. Wait until the operation completes, then quit DU and return to the installer. Now shutdown the computer for a couple of minutes and then restart normally.
If DU reports errors it cannot fix, then you will need Disk Warrior (3.0.3 for Tiger) and/or TechTool Pro (4.1.1 for Tiger) to repair the drive. If you don't have either of them or if neither of them can fix the drive, then you will need to reformat the drive and reinstall OS X.
Second, clone the system to your external drive:
1. Open Disk Utility from the Utilities folder.
2. Select the startup volume from the left side list.
3. Click on the Restore tab in the DU main window.
4. Drag the startup volume to the Source entry field.
5. Select the backup volume from the leftside list and drag it to the Destination entry field.
6. Check the box to Erase Destination. Skip this step if you've already formatted the drive.
7. Double-check you got it right, then click on the Restore button.
After the cloning is completed open the Startup Disk preference pane and select the external drive system then click on the Restart button. After the system reboots from the external drive do the following:
1. Open Disk Utility in the Utilities folder of your Applications folder.
2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Click on the Partition tab in the DU main window.
3. Set the number of partitions from the dropdown menu to 1 Partition. Set the format type to Mac OS Extended Journaled. Click on the Partition button and wait until the volume mounts on the Desktop.
4. Select the volume you just created (this is the sub-entry under the drive entry) from the left side list. Click on the Erase tab in the DU main window.
5. Set the format type to Mac OS Extended Journaled. Click on the Options button, check the button for Zero Data and click on OK to return to the Erase window.
6. Click on the Erase button. The format process will take 30 minutes to an hour or more depending upon the drive size.
7. When the formatting is completed clone the external drive back to the newly formatted internal drive using the same procedure as you did before, except that the external drive becomes the Source and the internal drive becomes the Destination.
Doing the above eliminates the need to reinstall OS X and will preserve your system exactly as it is currently without any data loss.