This month we will discuss maintaining your Mac files and recovering from apparent disaster. Like any other computer, over time your Mac will accumulate a number of files, some of which, for one reason or another, may become corrupt and interfere with the computer’s operation. Sometimes that interference can be downright inconvenient; other times simply disastrous.
To minimize the likelihood of your Mac suffering such an affliction, spend a little time keeping the files and the filing system in good order and repair. You can acquire several utilities to facilitate this process. Some come without charge; others you must buy commercially.
Apple’s Disk Utility
Every copy of the Mac OS comes with a copy of Apple’s Disk Utility Program. Use Disk Utility as your first line of defense against problems with your Mac. During the installation process, the OS installer placed a copy of Disk Utility on your hard drive. As you will soon discover, Disk Utility (like most other disk repair utilities) has a very limited capacity to correct problems on the operating system drive (the boot drive). To use Disk Utility most effectively, however, you must boot to a drive other than the one you want to fix. You can make an external disk drive bootable by installing an operating system on it. Booting to that drive allows you to then use the copy of Disk Utility on that drive to repair the internal Drive. Disk Utility has two separate checks it can run for you. The first (“Disk First Aid”) checks for consistency, overlapping programs, and minor structural problems. The second (“Repair Permissions” checks for problems with permissions. Disk Utility can do the latter on the boot drive; the former requires booting to a second drive.
For reasons that I have never understood, sometimes a problem disk is repairable only by booting to the OS install CD or DVD and then using its copy of Disk Utility. Logically, it should not be that way; but not everything about computers is logical, and it really is that way. [If you don’t know how to boot the Mac OS Install CD/DVD, you have several choices: (1) insert the CD/DVD into the computer when it is running, double click on the install icon, and it will restart booted to the CD/DVD; (2) restart the computer with the install CD/DVD in the optical drive and hold the “C” key down; (3) insert the CD/DVD in the computer when it is already up and running, open system preferences, and select the CD/DVD as the startup disk; or (4) insert the CD/DVD into the computer and hold the Option key down when it starts to boot/reboot. The computer will show all bootable disks connected to the computer. Pick the CD/DVD and tell it to continue with the boot process.
As a preventive maintenance matter, you should run Disk Utility prior to any system upgrade, and, depending on use, once every couple weeks. A light user might run it monthly; a very heavy user, weekly. Additionally, any time a problem appears, turn here first. Run the Disk Repair feature and then go back and run Repair Permissions. As you may know, Apple built Mac OS X on a UNIX base. In UNIX, permissions assume significant importance; that has carried over to the Mac OS X. Improperly set permissions can make it hard to get your Mac to behave properly. I run the repair permissions utility weekly, every time I install a system upgrade, and whenever the computer appears to have a problem.
When Disk Utility Doesn’t Work: The Big Three
Some problems exceed Disk Utility’s abilities. For that reason, the well-prepared Mac owner has acquired a few third-party disk repair utilities. I have three that I rely on extensively: Symantec’s Norton System Works (particularly Disk Doctor), TechTool Pro 4.01 from Micromat, and Alsoft’s DiskWarrior 3. While these three repair utilities do overlap some, each has some features and repair capabilities that the other lacks. I keep all of them available to me for handling disk maintenance and emergency repairs. In an emergency situation, I will run Disk First Aid and Repair Permissions first. If it doesn’t solve the problem, I will try Disk Warrior. If Disk Warrior runs into problems it cannot repair, I will try to repair them with Disk Doctor or Tech Tools, then try to run Disk Warrior again. If Disk Warrior still doesn’t work, I will use the computer as best I can until I can reformat the drive and use my backup data to restore it to a working configuration.
DiskWarrior will make repairs to the disk structure and then rebuild and optimize the disk directory. Disk Warrior cannot rebuild the directory on the boot disk (the disk with the controlling operating system, so you must either boot to the Disk Warrior CD or install Disk Warrior on a bootable external disk drive. As was the case with Apple’s Disk Utility, you will find times that the program cannot fix your disk when run from an external drive, but can when run from the Disk Warrior CD. Disk Warrior works technological miracles; I have seen Disk Warrior save drives that have become unbootable. It seems to fix more problems than any other utility program I have tried. Additionally, after rebuilding he directory, you will likely find your computer running a bit faster. If you run Disk Warrior once every other month, you will avoid many potential problems.
Both Disk Doctor and Tech Tools Pro repair volume structure problems and file problems. They work differently and will each repair some problems the other doesn’t. I run one or the other for maintenance purposes on a monthly basis.
Other Maintenance/Repair Techniques
Unix Maintenance Programs
OS X has a number of Unix repair programs built into its structure. The system normally runs those programs on its own when the computer is idle, often late at night or in the early morning. If you shut your computer off at the end of the day, the operating may not have the opportunity to run its maintenance programs. You can solve this problem by running them manually through the terminal program that comes with the OS, or you can get a third-party program such as MacJanitor (free, personalpages.tds.net/~brian_hill/macjanitor.html) or Cocktail ($11.95, www.macosxcocktail.com/), which provide a front end to allow you to run Unix maintenance programs without entering terminal. To run the programs manually, you must open the terminal (it should be in the Utilities subfolder of your Applications folder). You will need an administrator password. You will want to run the following commands, one at a time:
sudo periodic daily
sudo period weekly
sudo periodic monthly
Proper and timely maintenance of the disk and its filing system and folders will often prevent minor problems from becoming more serious and save you considerable aggravation down the line.