Self-diagnosing Your Sick Mac
When your Mac is sick, the first thing you want to do is to find a utility to console you. Macs are solid computers that some of us have come to think of as being maintenance-free, but any computer is bound to have some trouble within its lifetime. Here are some tricks to solving your problems, or at least finding the cause of them.
For simplicity's sake, lets exclude hardware issues, as they are very hard to repair without replacement parts or professional diagnostic tools. If you have an obvious hardware problem, seek the assistance of an Apple Authorized Service Center. So, setting hardware issues aside, lets look at the most over-prescribed solution. Most phone tech support, from Apple or anyone else, will recommend reformatting your hard drive and restoring from the original discs shipped with your Mac. This tactic is often a sledgehammer solution for a tack-nail problem. Of course it will solve virtually any software problem (until you re-install some piece of software that was the cause of it in the first place), because you're starting from scratch. But if the problems persist after a reformat and reinstall, then it's almost always a hardware problem. This is why it is universally used for professional support. Expect to hear it when calling for computer tech support. However, we are going to look at different approaches, ones that you should use when trying to solve your own issues.
Clean installation is not necessarily the first thing to try, but can be very successful in solving problems. It's almost as effective as reformatting, but obviously not as destructive to your data. A "Clean Install" will completely rewrite your System Folder with a known good one. The advantage with this is that it will only replace system files while keeping your own files, applications, and settings just as they were.
This is how you go about doing a Clean Install: Boot up off your OS X install disc (hold down the "C" key as it gets ready to boot). This could be a DVD or CD that came with your computer, or a full version you bought to upgrade the OS on your system. Click through the menus until you are asked to pick an installation disk. Most often you will only have one choice, but even then you will need to click on the hard drive that has OS X installed on it. Instead of selecting "Continue," first click on "Options." You will be presented with another screen. That screen will have three options. The one you want is marked as "Archive and Install." Make sure that the check box with "Preserve Users and Network Settings" has a check mark in it. Click "OK" and continue with the installation. After your computer has finished installing and has restarted, everything should look just like it did before. Check to see if your problem is fixed. You will need to run "Software Update" because the Clean Install will have removed any system updates you have installed from the web.
If that sounds too drastic or you don't have any OS install discs, try a "Safe Boot." Safe boot is a way of starting your Mac with only the bare minimum system software needed to run your computer. This is useful when you have installed new software that crashes your computer on startup. It can be hard to uninstall something if it crashes your computer before you can do anything. Safe Boot is easy to use. When your computer starts, hold down the shift key. The loading OS X screen will have a little "Safe Boot" message on it. When you see that you can let go of the shift key. Uninstalling software will be much harder but at least you have a chance of finding the offending files now. If you have not installed anything but are having problems that are fixed by booting to "Safe Boot" mode, try Repairing Disk Permissions from the Disk Utility and delete all the startup items found in the Users System preference panel.
If you can't even get your computer to boot in "Safe Boot" mode, try a "Verbose mode" startup. Do this by holding down the "Apple" key and "V" key on startup. Instead of seeing the grey Apple screen with that spinning cog, you'll see the Apple Unix loading text. If it stops loading, make note of what the last thing on the load list was. That can tell you where the problem is. Search the web to see if others have had the same problem and see what they have done. It may take you a little research to find a fix for the problem but this is what troubleshooting is all about. Now you see why phone tech support has you start from scratch and format your hard drive... it's much faster.
There are times when your computer does not lock up and boots fine but may have one stubborn program that will crash randomly throughout the day. When troubleshooting this, you will need a program Apple includes called "Console." Console is just one of many tools Apple gives you to use when troubleshooting your Mac, and is found in the Utilities folder in the Applications folder. This little app will view all the log files on your computer. Did you know your Mac is constantly taking notes on what it's doing? These notes are written in computer shorthand and can be hard to interpret. So just don't expect to find a smoking gun written here. When you start up Console, you will be presented with a window. On top will be four buttons and a "filter" text box. Clicking on the "Logs" button will open a left hand navigation pane. From that pane select "console.log," which will tell you all the logs being written to on your computer. This is the most helpful because you can see error messages you, the user, are never shown. If there is an application crash, that application will have a crash log that gets a new entry. You can view those logs from Console as well, but they do take some skill to read. Instead, look for any other crashes or error messages that you were unaware of. Two applications could crash at the same time but you may have only noticed the one you were working in. Seeing what's happening to your system around the time of an application crash can tell you if there is a conflict between two items. Perhaps that beta web browser crashes iPhoto. Console can help you find that out by showing you a history of problems preceding a crash.
Troubleshooting your Mac can take time and skill, but almost all the tools are included with your computer. Probably the most useful for you is going to be the OS install disks, because although I have shown you how to troubleshoot your Mac and dig into the guts of it, you may still just want to just do a Clean Install. Working through Console to find a problem will often take longer than a Clean Install and could cause you to pull out most, if not all, of your hair. It is good to know how to fix the little things on your computer but the reality is that the sledgehammer approach can save you time and frustration. If you have the time and will to geek out, by all means do... otherwise swing that hammer.