This article provides guidelines to help troubleshoot various system "freeze" symptoms associate with Macintosh computers.

The following system "freeze" symptoms are covered in this article:

My computer "freezes:

• At the happy Macintosh during startup
• While loading system extensions during startup
• After startup as the Finder is loading
• While the computer is sitting idle
• When launching, using, or quitting application "X"
• When printing from application "X"

At the "happy Macintosh" during startup

1. Turn computer off from the back of the computer.

2. Temporarily disconnect external SCSI and serial devices.

3. Wait 7 - 10 seconds for the drive to spin down.

4. Turn computer back on.

5. If computer continues to freeze at the "happy Macintosh", try starting up from the system software CD-ROM disc or a Disk Tools floppy disk. The procedure for starting with the CD-ROM disc is documented in the User's Guide. Once you have started up from the CD-ROM disc or Disk Tools disk, run Disk First Aid to make sure hard disk is OK. You may also test the drive with Apple HD SC Setup or Drive Setup.

6. If computer continues to freeze at the "happy Macintosh" while starting up from the CD or Disk Tools floppy disk, the computer should be serviced by an Apple Authorized Service Provider.

While loading system extensions during startup

Troubleshoot this issue as an extension conflict.

1. Turn computer off from the back of the computer.

2. Temporarily disconnect external SCSI and serial devices

3. Start up the computer and hold down the space bar during startup to open the Extensions Manager control panel.

Select the extension set called "System 7.5.x Only."

4. If the computer still freezes during startup, perform a clean installation (or restore new system software) to alleviate possible corrupted system software.

5. If the computer still freezes during startup after a clean installation of system software, the computer should be serviced by an Apple-authorized service provider.

After startup as the Finder is loading

Troubleshoot this issue as an extension conflict.

1. Restart from the Special menu or the keyboard by pressing and releasing the Command-Control-Power keys.

2. Start up the computer and hold down the space bar during startup to open the Extensions Manager control panel.

3. Select the extension set called "System 7.5.x Only."

4. Start up with Extensions disabled (by holding the Shift key during start up). If the computer starts up, temporarily remove the Fonts and Preferences folders from the System Folder. You may place them on the Desktop, for example. Restart the computer. If the issue does not persist, a damaged font suitcase or preference file is causing the issue.

5. If computer still freezes, perform a clean installation of the system software or restore new system software to alleviate possible corrupted system software."

While the computer is sitting idle

Troubleshoot this issue as an extension conflict.

1. Restart from the Special menu or the keyboard by pressing and releasing the Command-Control-Power keys.

2. Start up the computer and hold down the space bar during startup to open the Extensions Manager control panel.

3. Select the extension set called "System 7.5.x Only."

4. Check to see if any screen savers have been added to the System Folder. Temporarily disable or remove any screen savers as they may cause this symptom if they are incompatible.

5. If system still freezes while sitting idle with extensions off, perform a clean installation of the system software or restore new system software to alleviate possible corrupted system software.

When launching, using, or quitting application"X"

Troubleshoot this issue as a possible low memory situation or as a possible application conflict with the system software and/or an extension conflict.

1. Restart from the Special menu or the keyboard by pressing and releasing the Command-Control-Power keys.

2. Once computer has started back up, choose About This Macintosh from the Apple menu in the Finder.

3. Check the Largest Unused Block of memory in the About This Macintosh window.

4. Check the Memory Requirements of the application to be sure that there is enough free memory for the application to launch. It's important for the application to have at least the Minimum size of memory available to run. (For more information refer to Macintosh Guide's Application Programs topic, "How do I change the memory a program uses?")

Note: It may be necessary to enable Virtual Memory in the Memory control panel to give the application enough memory to run.

5. If the computer still freezes, restart the computer and hold down the space bar during startup to open the Extensions Manager control panel.

6. Select the extension set called "System 7.5.x Only."

7. Try to launch application again.

8. If the computer still freezes when launching the application, try starting the application with Modern Memory Manager (for Power Macintosh computers) or 32-bit addressing (for earlier Macintosh computers) turned off. Some older applications may not be compatible with these options. Contact the developer for a more up-to-date version of the application.

9. If the computer still freezes, the application may not work with your computer. Check the application's documentation or contact the developer of the application to determine if the application will work with your computer.

First, troubleshoot this issue as a possible low memory situation. Second, troubleshoot this issue as a possible print driver and application or system software conflict.

1. Restart from the Special menu or the keyboard by pressing and releasing the Command-Control-Power keys.

2. Once computer has started back up, choose About This Macintosh from the Apple menu in the Finder.

3. Check the Largest Unused Block of memory in the About This Macintosh window.

4. Check the Memory Requirements of the application to be sure that there is enough free memory for the application to launch. It's important for the application to have at least the Minimum size of memory available to run. (For more information refer to Macintosh Guide's Application Programs topic, "How do I change the memory a program uses?")

Note: It may be necessary to enable Virtual Memory in the Memory control panel to give the application enough memory to run.

5. If the computer still freezes when printing and you are using Background Printing, try increasing the Memory Requirements for the PrintMonitor application if issue only occurs during Background Printing. The PrintMonitor is located in the Extensions folder within the System Folder.

6. If the computer still freezes when printing, try disabling the Background Printing option in the Chooser or turn on Virtual Memory to increase the memory available for Background Printing.

7. Many print drivers including Apple's LaserWriter and StyleWriter drivers allow the user to enable to Background Printing. If there is not enough free memory for Background Printing to run, the computer may freeze during printing.

If the computer still freezes when printing, the print driver may not be compatible with the application or system software. Check the printer's documentation or contact the manufacturer of the printer to determine if the print driver is compatible with your computer.