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Troubleshooting Startup Problems

Use the following table to eradicate any start-up problems you may be having:

STEP	PROCEDURE	RESULT	ACTION
1	Disable Extensions: Restart your machine and hold down the SHIFT key.	If your machine starts up without loading extensions, then you probably have an extension conflict. If not, go to Step 2.	See: Troubleshooting Extensions
2	Boot from Disk Tools Disk: Restart your machine by booting from the Disk Tools floppy disk.	If your machine starts from floppy disk, you may have corrupt system software or a drive problem. If not, go to Step 3.	See: Using Disk Tools
3	Disconnect External Devices: Disconnect all external devices (such as SCSI devices, printer, networking, extra monitors, etc.)	If your machine starts up with no external devices attached, you have a possible out-of-date drive or a SCSI ID or software conflict. If not, go to Step 4.	See: Troubleshooting Peripherals
4	Reset PRAM: Press and hold Command-Option and the letters P-R at startup to zero out the information the machine maintains on parts, devices, and Finder and network settings.	If your machine starts up after resetting PRAM, then there was most likely corrupt informationin the Paramter RAM on you machine. If not, go to Step 5.	See: What's in PRAM?
5	Perform a Clean Install: Follow the steps in "The Quick Fix" section of MacintoshOS.com's Troubleshooting section to perform a clean install of system software.	If your machine starts up after a clean install, then one of the files you added, or one of your old system files was corrupt. If not, go to Step 6.	Carefully go through the "Old System Folder" folder you created during the clean install; look for fonts, extensions, control panels, etc. that you might need and put them back where they belong.
6	Try these last ditch efforts: - Try other disk utilities. - Reformat the drive and reinstall a recent backup. - Contact vendors of Third Party hardware or software you use.	If your machine starts up after trying these efforts, then you have successfully corrected the problem and are ready to work.	Make regular backups in case you have trouble again (but don't destroy the backup you restored in this step).
7	.	If you machine still doesn't start up, there is most likely a hardware problem.	Contact your local Service Provider to isolate and correct your problem.

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Troubleshooting Actions
he aforementioned actions and procedures may help you resolve a number of common problems, from damaged or missing files, to extension incompatibilities, to SCSI termination problems. If you have any third-party (non-Apple) devices or software, please adhere to the recommendations of the manufacturer if they differ from the more general instructions presented here. As a precaution, you should back up important files regularly to minimize the risk of data loss.

Troubleshooting Extensions
Extensions load into memory at system startup time, and actually change the way the operating system works. When they are incompatible with the version of the system software you run, corrupt, or conflicting with one another, they can cause unexpected results.

Extensions are sometimes also called INITs; they are usually in the Extensions Folder or the Control Panels folder within your System Folder. Sometimes they are at the root level of the System Folder itself. As they load into memory at system start-up time, their icons usually appear on the bottom of your screen.

To troubleshoot extensions, follow these steps:

• Restart with your SHIFT key down, until you see the box with the message Welcome to Macintosh -- Extensions Off. If the problem goes away, then continue these steps to determine which of your extensions are causing the problem.
• Restarting with extensions off also disables file sharing and virtual memory. Use the Memory Control Panel to turn Virtual Memory, 32-bit, and Memory Manager OFF and to turn the Disk Cache down to 96K or below. Use the Sharing Set Up control panels to turn File Sharing OFF. Restart. If problems do not go away, continue with these steps.
• Check your Extensions Folder, your Control Panels Folder, and the root level of your System Folder for non-Apple chooser and system extensions and control panels (such as virus protection, screen savers, compression utilities, etc.). Drag these outside of your System Folder (make a new folder for them named Disabled Extensions). Restart. If the problem goes away, then you have succeeded in removing the problem extensions. Continue with Step 4. Otherwise, check through your System Folder again for extensions you may have overlooked.
• To determine which of the extensions you removed was causing the problem, drag the extensions one at a time onto the icon of your closed System Folder. The system puts them away where they belong. Restart after each addition. When the problem returns, you will know that it is the last extension you dragged to the System Folder. Remove it and restart. Check its version number for compatibility. Try reinstalling it from original floppies, or contact the software vendor.
• If you are still unable to find the culprit, do a Clean Install by following the steps outlined in the "The Quick Fix" section of MacintoshOS.com's Troubleshooting section.

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Using Disk Tools

The Disk Tools Disk that comes with your system software includes a System Folder and two utilities:
• Disk First Aid
• Apple HD SC Set Up

When you are having trouble starting up your Macintosh from the hard drive, you should start up from the Disk Tools Disk. This way you can repair any problems on the hard drive (which you cannot do when it is your startup drive). Insert the disk into the floppy drive and turn on the Macintosh. The Disk Tools Disk icon displays in the upper right corner, and your hard disk icon should display below it.

Disk First Aid:

Use Disk First Aid to check your internal hard disk for directory problems. Simply launch Disk First Aid, highlight the drive icon for the applicable hard drive, and click on Verify. (On older versions of Disk First Aid click Drive until the selected drive is your internal hard disk, then click Open and Start.)

If Disk First Aid finds problems it cannot repair, you may want to try other third party disk utilities to correct the problem. However, if you cannot repair the disk, you need to reformat it. Make sure you have a backup of your data before reformatting. If you don't have a backup, you may want to take your drive to a Service Provider that specializes in hard disk recovery.

Apple HD SC Set Up:

Apple HD SC Set Up is a disk formatting utility for Apple hard disks. If you have a third party hard disk in your Macintosh, you get the message that Drive Selection Failed when you launch Apple HD SC Set Up. In this case, use the third party disk formatting utility that came with your drive, or contact the vendor of the drive.

To use Apple HD SC Set Up on an Apple hard disk, launch the utility and simply click the Update button to reinstall the hard disk drivers. You can also use the Test button to test the hard disk, and Initialize to reformat.

NOTE: Initializing erases all data on your hard disk. Ensure you have a backup before doing this.

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Troubleshooting Peripherals

SCSI Devices
If you have SCSI devices connected to your Macintosh, make sure that you have followed the vendor's instructions for installation. Specifically, check:

• Termination -- SCSI chains should be terminated at the beginning and end of the SCSI chain. Your internal hard disk (if any) is considered the beginning of the chain, and has terminating resistors. Whatever device is last in your chain should also be terminated. Check the manuals that came with the devices to discover if they are internally terminated. If not, the last device needs an external terminator. Devices in the middle of the chain should not be terminated. Again, check the manuals or contact the vendor.
• Unique SCSI ID -- Each device on the SCSI chain requires a unique ID number between 0 and 7. ID 0 is generally used on internal hard disks; ID 7 is reserved for the Macintosh itself. This leaves numbers 1 through 6, which you can assign to your external devices. Consult the manuals that came with your devices to determine how to set their IDs.
• High-quality SCSI cables -- Use high-quality cables, the shorter the better (three feet or less). When chaining more than one external SCSI device, try to use the same brand of cable.
• Starting up -- External SCSI devices should be powered on, one at a time, before starting up the Macintosh. When shutting down, shut down the Macintosh first. Once the Macintosh has powered down (the screen goes dark or you get a dialog box telling you that it is OK to Shutdown) then turn off each device, if desired. Never connect or disconnect SCSI cables when any device is turned on. Do not start up the Macintosh with a SCSI device turned off, unless the manufacturer specifically says in the manual that this is acceptable. Network Connections.

If you have problems starting up your Macintosh with a network connector attached (such as a LocalTalk connector box), there may be problems on the network, or with the connector itself. This usually occurs at the Welcome to Macintosh screen when the computer freezes. First, swap out the connector with a known good one; if problems persist, consult with your network administrator.

Apple Desktop Bus (ADB) Devices

If you are experiencing problems starting up when an ADB device, such as a mouse or tablet, is connected, first make sure the connections are snug. Try another ADB port, if your Macintosh has more than one. If you are still having problems, contact the device vendor.

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What's in PRAM?

Parameter Random Access Memory (PRAM) is a small amount of memory continually powered by a lithium battery to retain its contents even when the machine is shutdown. PRAM maintains information such as: background color, default video selection, network information, serial port information, and default highlight color.

The Macintosh 128K, Macintosh 512K, and Macintosh 512KE contain 20 bytes of Parameter RAM (PRAM). The rest of the computers in the Macintosh family have 256 bytes of PRAM (except for the Macintosh Portable which has 128 bytes). Most of the information stored in PRAM isn't documented in any technical manual.

Even though you may not know what in PRAM is causing problems on your machine, resetting this information can often be an important troubleshooting step. Particularly when serial devices are connected to the machine, or when networking software is in use.

After resetting PRAM, your environment may be a bit different; you should "re-customize" it to your liking. Resetting the PRAM resets your Macintosh to the factory defaults, so anything you've customized (like background or highlight color) is reset, your alert sound may be different, and AppleTalk will most likely be turned off. Reset your control panels to what you had before.