Trying Quick Fixes

An effective troubleshooter quickly and systematically eliminates areas to explore and continually isolates likely solutions. Trying quick fixes is one of the most effective steps in this process.

A quick fix is a repair action that:

• Can be performed quickly

• Involves little or no risk of harm to the system

• Has little or no cost

A quick fix is not necessarily the most likely solution to the problem, but because it's easy to perform and takes little time or expense, it's worth trying. Trying quick fixes gives you valuable information about where the problem is not.

For convenience, we divide the quick fixes applicable to troubleshooting the operating system into three increasingly invasive levels.

Trying Quick FixesInnocuous

For software-related problems, there are several quick fixes you can try that do not alter the system (refer to "Mac OS X Quick Fixes" in Appendix A, "Apple General Troubleshooting Flowchart"):

• Use System Profiler. For instance, you can use System Profiler to verify that the system detects a connected FireWire drive in situations where the volume doesn't appear on the Desktop.

• Start up from a known good operating system (such as the Mac OS X Install DVD), restart, or power off. If you press the Option key when you start up the system, the computer will display the Startup Manager screen, which lists drives and partitions with System folders. From this list you can select a different volume to boot from. The underlying goal is to start up using a known good operating system, thereby narrowing the problem to the original operating system (if the startup succeeds) or eliminating the operating system (if the startup fails).

  MORE INFO

  Refer to Knowledge Base document 107199, "Mac OS X: If your computer stops responding, 'hangs', or 'freezes.'"

  
  

• Use Disk Utility to verify and repair hard disk directory damage.

Trying Quick FixesLess Innocuous

Less innocuous quick fixes alter the user's system in some minor way. For example:

• You can create a new administrator user to test whether faulty user settings or preferences were causing the original problemalthough this will not resolve issues with system-wide preferences or the local NetInfo database. Or, when troubleshooting an application such as iMovie, you can eliminate the possibility of a corrupt preferences file (plist file) by moving or renaming the application's preferences file.

  MORE INFO

  Refer to Knowledge Base document 25398, "Mac OS X: How to troubleshoot a software issue."

  
  

• As mentioned in Lesson 6, "Application Environments," you can force quit an application if it is not responding or is causing problems. If the application works fine after restarting, no further action is required. However, if the application continues to be problematic, you need to continue trouble shooting.

• You can try logging in as a different user. You may find that another user account works fine, allowing the user to complete any urgent tasks. You can then compare the working user account against the nonfunctional one to find out what difference is causing the problem.

• You may need to update the firmware on the computer. You can determine the current firmware version by running System Profiler (if the computer is functional enough), or by restarting into Open Firmware (restart while pressing Command-Option-O-F until the Open Firmware message appears).

  MORE INFO

  Refer to Knowledge Base document 60351, "Determining BootROM or Firmware Version."

  
  

• Use the Verify/Repair Disk Permissions in Disk Utility. As mentioned in Lesson 3, "User Accounts," erratic system behavior could be caused by incorrect permissions set on the boot volume.

Trying Quick FixesInvasive

Invasive quick fixes, such as reinstalling the operating system, are more risky, because they alter the computer in some way. Before attempting invasive quick fixes, complete each of the following tasks, as appropriate:

• Make a backup of user data. You must do this before updating, reinstalling, or otherwise modifying the software on a system. This backup ensures that you can restore the system to its original state if you need to do so. If the system is unable to boot and you have a FireWireenabled system, you may be able to start up the system in Target Disk Mode, which allows you to connect it to another system and copy critical data files.

• Make sure you are using only known-good software to modify the system. Avoid introducing new problems while trying to solve the original one.

• Look for the latest versions of software that you intend to update or reinstall. Be careful not to add new software components that can adversely affect applications and other software that the user has placed on the system.

If the problem occurs only with a single application, reinstalling the application may fix the problem. It is possible that key components for the application had been deleted or corrupted.

If the computer is having difficulties in the BootROM startup sequence, you may wish to reset the parameter random-access memory (PRAM). Resetting the PRAM will reset any Open Firmware variables that may have been incorrectly entered. Resetting the PRAM also resets the non-volatile random access memory (NVRAM).

Reset PRAM by pressing Command-Option-P-R during startup until you hear the startup sound twice. To reset NVRAM independently, start into Open Firmware and enter

reset-nvram

These changes are invasive in that changes to the system are required and could have repercussions later. For example, resetting NVRAM immediately after a kernel panic erases potentially useful log information.

Problem ScenarioQuick Fixes

After you've verified the problem, trying relevant quick fixes can save time and provide more information.

Here's an example. A home user is having a problem with his Internet connection. It worked fine yesterday, but today he cannot connect to any sites from Safari.

After verifying that he has not made any changes since his connection was working, you have him check network settings. It appears that he is getting a correct IP address and can even communicate between two machines on his home network. Because his local settings seem to be unchanged from yesterday and his home network seems to be working, you have him cycle power to his cable modem. After the cable modem powers up, he is able to connect. While incorrect network settings frequently cause home networking problems, resetting base stations, cable modems, and routers are also common fixes.