Mac Tip Of The Day #418

Apple has changed the way in which users can listen to their music even when the screen saver is running.

To be able to play your music and podcasts in screensaver mode as shown in the window above you will need to navigate to the “System Preferences” followed by “Desktop & Screen Saver.” Then make sure you are in the “Screen Saver” tab and “iTunes Artwork” is selected as shown below:

The example you see on the right hand side will be how your album artwork is displayed on the screen when the screensaver is active. Depending on how much music you have in iTunes this will change each time your Screen Saver is activated therefore allowing you a variety of options.

The options button presents the following to the user:

Rows simply indicates how many rows of album artwork will be displayed at any given time. Less rows will result in larger artwork.

The delay is set to a default of 2.0 seconds and directly relates to how frequently the album artwork will flip in the screen saver therefore presenting users with new albums to select from.

You are not able to select specific tracks using this method. You are able though to use the iTunes play/pause, next and previous buttons along with the volume up, down and mute keys on your keyboard without cancelling the screen saver. However, other keys not assigned to iTunes controls will cancel the screen saver.

In addition to this control you can also use the mouse controls to navigate between album artwork to change the album, pause a playing track or simply exit. All of these functions are represented in the image at the beginning of this article.

At present you are unable to select specific genres or playlists. You are also not able to select specific tracks or see the track information.

Mac OS X10.0: Computer With SCSI Chain Does Not Start up or Stops Responding

A computer running Mac OS X may not start up or may stop responding if the SCSI chain is improperly terminated.

Products Affected

Mac OS X 10.0

Symptom

The computer does not start up, or stops responding. The mouse pointer may appear as a spinning disc, and the computer may appear unresponsive.


Solution

This is the result of an improperly terminated SCSI chain. Verify that all SCSI chains are terminated at both ends. This includes terminating any SCSI card that is the last device in the chain.

Note: A SCSI chain that worked with Mac OS 9 may not work with Mac OS X. Mac OS 9 is more tolerant of improper termination than Mac OS X. A properly terminated SCSI chain should perform better, regardless of the version of the Mac OS.

Mac doesn't start up from disc

Symptoms

If your Mac stops responding when starting up from a Mac OS X Install DVD, learn about some troubleshooting steps you can use. 

Products Affected

Mac OS X 10.4, Mac OS installation/setup (any version), Mac OS X 10.6, Mac OS X 10.5

Resolution

Try these troubleshooting tips one at a time until you are able to start from the disc:

1. Verify that the shiny side of the disc is clean (no particles or smudges on it). Here are some tips for cleaning a disc.
    
2. Make sure you are using the disc that came with the computer, or a newer disc that contains a compatible version of Mac OS X (look at version on the label of the DVD). Please see:
   • Don't install a version of Mac OS X earlier than what came with your Mac
   • Mac OS X versions (builds) included with Intel-based Macs
      
3. To verify that your Mac is attempting to start from the disc, hold the C key as your Mac starts up. You may hear access sounds from your computer's optical drive.
   • If holding C does not help, hold the Option key during startup. Startup Manager should appear. Select your Mac OS X disc icon, then press Return.
   • If Startup Manager does not appear, make sure you are using an external Apple keyboard (directly connected), or a portable Mac's built-in keyboard. Some third-party keyboards may not be recognized in time for Startup Manager to appear.
   • If you are able to start from your hard disk, you can use Startup Disk preferences in System Preferences to select the disc, then restart.
      
4. Temporarily disconnect USB and FireWire devices connected to your computer. If you are not using a portable Mac, connect your Apple keyboard and mouse directly to your Mac. If this resolves the issue, reconnect USB and FireWire devices one a time until the issue occurs again. Once a problematice device is located, contact the manufacturer for assistance.
    
5. Your Mac may benefit from a firmware update. The latest firmware updates are available from Apple Support Downloads.
    
6. If the issue persists, shut down your Mac, then remove third-party hardware upgrades such as third-party memory (RAM) and third-party expansion cards. If this resolves the issue, contact the manufacturer of the product for assistance.

Additional Information

In rare cases, a kernel panic message may appear when you can't start from a Mac OS X disc.

Note: If you're having difficulty starting up from your hard drive, see Gray screen appears during startup instead.

Mac OS X10.0: Computer With SCSI Chain Does Not Start up or Stops Responding

A computer running Mac OS X may not start up or may stop responding if the SCSI chain is improperly terminated.

Products Affected

Mac OS X 10.0

Symptom

The computer does not start up, or stops responding. The mouse pointer may appear as a spinning disc, and the computer may appear unresponsive.


Solution

This is the result of an improperly terminated SCSI chain. Verify that all SCSI chains are terminated at both ends. This includes terminating any SCSI card that is the last device in the chain.

Note: A SCSI chain that worked with Mac OS 9 may not work with Mac OS X. Mac OS 9 is more tolerant of improper termination than Mac OS X. A properly terminated SCSI chain should perform better, regardless of the version of the Mac OS.

Mac OS X: Changing or resetting an account password

Summary

Learn how to change or reset an account password in Mac OS X, including the original administrator account password. You might need to do this when someone has lost or forgotten his or her account password.

Products Affected

Mac OS X 10.3, Mac OS X 10.2, Mac OS X 10.1, Mac OS X 10.4, Mac OS X 10.6, Mac OS X 10.5

Tip: If you forget your login password, and your home folder is protected by FileVault, see I forgot the password to my encrypted home folder.
 

Resetting a user's password

Note: These steps are for Mac OS X v10.3 or later. For information about resetting a password in Mac OS X v10.2.8 or earlier, see the Additional Information section below.

1. Log in with an administrator account. Tip: If you don't know the password of any administrator accounts, see "Resetting the original administrator account password" below.
2. From the Apple menu choose System Preferences.
3. From the View menu choose Accounts.
4. Click the lock button if it appears locked; enter the administrator password.
5. Select the username whose password you want to change.
6. Click the Reset Password button (Mac OS X v10.3 and v10.4) or the Change Password button (Mac OS X v10.5 or later).
7. Enter a new password in both the Password and Verify fields, and add a hint if desired.
8. Click the Reset Password button (Mac OS X v10.3 and v10.4) or the Change Password button (Mac OS X v10.5 or later).
9. If a dialog box appears with the message "Your Keychain password will be changed to your new account password," click OK.

Important: Passwords for administrator accounts should not be blank.

Isolating issues in Mac OS X

Symptoms

By using the approach here, you can learn how to isolate an issue to its root cause, or at minimum to determine the sequence of events that causes the issue to occur. Using this approach may help you solve the issue, locate other support articles, write better posts to Apple Discussions, or communicate with AppleCare Technical Support.

Products Affected

Mac OS X 10.0, Mac OS X 10.3, Mac OS X 10.2, Mac OS X 10.1, Mac OS X 10.4, Mac OS X 10.6, Mac OS X 10.5

Resolution

Start by asking yourself basic questions about the issue that will help you describe it:

What is the issue?

When answering this question, be sure to note any alert or "error" messages that appear. Be sure to describe any unexpected hardware or software behavior, and any other details that seem relevant.

Users accustomed to reading logs should review them in Apple System Profiler for any relevant information. If you are not experienced with reading logs, it is generally best to ignore them unless instructed to search for a specific message.

When does it occur?

• If you can identify a sequence of events that lead up to the issue, be sure to document each.
• If the issue seems to occur at certain time intervals, be sure to record the times at which it happens. Does it happen only at certain times (for example, daily at 9:00) or on a periodic basis (for example, every 47 minutes)?
• If the issue occurs so irregularly that you cannot yet describe when it happens, the suggestions below will help you troubleshoot the issue over time by making certain changes, then watching to see if the issue stops.
• If the issue occurs at startup immediately following a third-party software installation, find out what you can do.
• You can also troubleshoot any other issues that occur during startup.

If these suggestions do not resolve your issue, contact AppleCare or your nearest Apple Authorized Service Provider for assistance.

When did the issue start?

Note any recent changes to the computer and its software, since they could affect the issue. Was any new software or hardware installed?

Check documentation

After you can describe the issue, check known documentation sources, searching on key terms you have identified.

If an application program is affected, first check any "read me" files included with it. These may describe known issues.

If the issue is with a third-party product, check the manufacturer's or publisher's website for information about the issue.

Up-to-date software and firmware?

As a general rule, make sure you are using the latest versions of Apple and third-party software for best compatibility. Also make sure your computer's firmware is up-to-date.

Is it a software or hardware issue?

Pay attention to important clues.

• If the issue seems specific to a certain application or Mac OS X feature, troubleshoot software before hardware.
• If the issue occurs as the computer starts up--unless the computer does not turn on at all-- troubleshoot software before hardware.
• For other issues, or when software troubleshooting does not produce a resolution, use the rest of this document.

Use Disk Utility to check for disk errors and permission issues

Such issues can contribute to other symptoms, but are usually easy to resolve.

Can you isolate to a hardware device?

Issues with a hardware device can sometimes appear to be software issues, but are not resolved with software troubleshooting. Eliminate hardware as a cause (or conversely, isolate the issue to software):

1. Disconnect external devices. If the computer is an iBook or PowerBook computer, disconnect all external devices. For an iMac, disconnect all devices other than the Apple keyboard and mouse. For a Power Mac, disconnect all external devices other than one display (which should be connected to an original, built-in video port), and the original Apple keyboard and mouse. If this resolves the issue, add devices back one at a time (shut down first if the device requires it) to further isolate the issue.
2. Insert the Apple Hardware Test CD that came with your computer (if one did). Use the extended test. If any issues are found proceed to step 3, or contact AppleCare or your nearest Apple Authorized Service Provider to arrange for diagnostics and service as necessary.
3. Shut down the computer and remove any third-party memory upgrades, expansion cards, additional hard drives, or other internal hardware upgrades. If you are not comfortable doing this, an Apple Authorized Service provider can assist. A service fee may be charged if the issue is not related to your Apple hardware. Alternatively, you may wish to skip this step and go to "Reinstall Mac OS X" below.
   • If the issue is resolved, add your devices back one at a time. When the issue returns, remove the most recently-added device. If the issue goes away again, you have identified the cause. If software was included with the device, try deleting and reinstalling it. You may also wish to contact the vendor or manufacturer of that device for specific troubleshooting steps.
   • You may want to test devices on all available ports into which they can be used. If a USB device works on USB port 1 but not on USB port 2, try connecting other devices to port 2. It is possible that your computer's ports aren't working properly.

Reinstall Mac OS X

If an issue persists, reinstalling Mac OS X should resolve it.

• For Mac OS X v10.6, simply reinstall Mac OS X v10.6 from its installation disc.
   
• For Mac OS X v10.2, 10.3, 10.4, or 10.5, perform an Archive and Install installation.
  Tip: You won't be able to return to your previous System following an Archive and Install installation, but you can select the "Preserve existing Users & Network Settings" option to retain your original applications and settings, documents, and user accounts.
• For Mac OS X v10.1.5 or earlier, reinstallation of Mac OS X requires erasing the Mac OS X volume. This is described in the next paragraph.

If the issue persists, back up any necessary data, start up from a Mac OS X Install or Restore CD, erase the Mac OS X volume, reinstall Mac OS X and restore any additional Apple software.

Reinstall additional software one item at a time, restarting the computer after each install. For best results, use the computer for several hours after each installation to determine if that particular software contributed to the issue. Reinstalling everything at once without noting when the issue returned may lead to a need to repeat this process.

Warning: Choosing Erase and Install will completely erase the contents of the chosen volume before installing Mac OS X. Be sure to back up your files before continuing.

Mac OS X, Mac OS X Server: Changing Privileges for System Software Components May Prevent Proper Startup

A computer may not start up correctly with Mac OS X if the privileges (or "permissions") have been changed for system software components. This may occur after a change of guest user privileges.

Products Affected

Mac OS X 10.0, Mac OS X 10.3, Mac OS X 10.2, Mac OS X 10.4, Mac OS X Server 10.3

Symptom

The computer does not start up properly.

Solution

Do not change the privileges for system software components. Instead, change your share point selection.

Some people change these privileges after noticing that the guest user has rights to some system software components. However, these privileges must remain in place for the computer to start up properly.

The proper way to address this concern is to make share points from individual folders, rather than making an entire disk a share point. This approach should also prevent you from making privileges changes to the entire startup disk when using the Workgroup Manager or Server Admin application included with Mac OS X Server.

For more information, see technical document 106805, "Mac OS X: Do Not Move 'mach_kernel' or Other System-Installed Files and Folders, Some of Which Are Normally Invisible".

Mac OS X: Issues after removing "etc" and/or "var" directory alias when started up from Mac OS 9

Products Affected

Mac OS X 10.0, Mac OS X 10.3, Mac OS X 10.2, Mac OS X 10.1, Mac OS X 10.4

Aliases to the "etc" and "var" folders may be visible when started up from Mac OS 9. These aliases shouldn't be removed.

This document applies to Mac OS X 10.1.5 or later.

When starting up in Mac OS X after having been started up from Mac OS 9, one or more of these symptoms occurs:

• The computer stops responding during startup. 
• The Setup Assistant reappears. 
• BSD commands that access files in etc and var fail.
• An alert box appears with a message that contains:
  "/etc/master.passwd: no such file or directory".

Do not delete the "etc" or "var" aliases, or any other Mac OS X-installed files or folders that are visible when started up from Mac OS 9. See "Mac OS X: "Broken Folder" Icon, Prohibitory Sign, or Kernel Panic When Computer Starts Up".

If these items were deleted, use these steps:

1. Start up in single-user mode. 
2. Type: mount -uw /
3. Press Return. 
4. Type: ln -s /private/etc etc
   
   If this alert appears: "File already exists," execute the following command, then repeat the last step:
   mv /etc /private/tmp/etc.delete 
   
   
5. Press Return. 
6. Type: mv /var /var.delete
   There is a space between "/var" and "/var.delete".
   
7. Press Return.
   Tip: If you see the message "No such file or directory," make sure that the spacing and spelling are correct, then repeat the last two steps. If you still see this message after the second attempt, continue to the next step. 
8. Type: ln -s /private/var var
9. Press Return. 
10. Type: ls -l | grep ">" 
    The character before "grep" is a pipe character ("|"), which is usually located above the Return key.
    
11. Press Return.
    
    
    Look for these two items in the output:
    
    lrwxrwxr-t  1 root  admin  {date} etc -> private/etc
    lrwxrwxr-t  1 root  admin  {date} var -> private/var
    
    If any of these are not present, repeat the necessary steps above until they are.
    
    
12. Type: reboot
13. Press Return.

My Mac is showing a flashing question mark !

Don't panic...

If you see a flashing question mark when you start your Mac, it's probably because it can't find the system software it needs to start up.

Usually, all you have to do to get your Mac back up and running is remind it where its software is.

In the olden days (Pre OS X) you could drag the System File out of the System Folder and then drag it back in and it would be re 'blessed'...

After the flashing question mark appears, one of two things may happen:

The computer starts up normally after a brief delay.

The computer does not start up.

If your computer starts up normally after a brief delay, you probably just need to reselect the startup disk in Startup Disk preferences (Mac OS X) or the Startup Disk control panel (Mac OS 9).

It's normal to see the flashing question mark when a startup disk has not been selected. In most cases, reselecting the startup disk is all that is required to resolve the issue.

Check the mouse and keyboard...

If the mouse button is held down during startup, this issue might occur. Make sure the mouse button isn't pressed.

If the issue persists, disconnect the mouse and keyboard before starting up as a test. Use your computer's power button to turn it off and on. If the issue persists, reconnect the keyboard and mouse.

More solutions to try

If your computer still starts to a flashing question mark, follow the steps for your Mac OS version below.

Steps for Mac OS X 

The possible causes and solutions for this symptom appear in the order that you should try them. If any step resolves the issue, you don't need to continue to the next one.

If at any time in this process you determine that your Mac OS X system software is missing, reinstall Mac OS X.

Mac OS X system software is stored in the System and Library folders at the top (root) level of your hard disk. It is also stored in folders that are invisible when started up from Mac OS X but that are visible when started up from Mac OS 9. If you have started up from Mac OS 9 and deleted folders that were unfamiliar to you, you may have accidentally deleted your Mac OS X system software. If you're not sure, save reinstallation for your last option.


Start up from a system software CD or DVD, and repair your disk using Disk Utility:

Insert the Mac OS X Install or Restore disc.

Restart the computer, then hold the C key during startup.

From the Apple menu, choose Disk Utility. Do this in the first screen of the Installer. Don't click Continue. If you click Continue in a Mac OS X Installer version earlier than 10.2, you must restart from CD again.

Click the First Aid tab.

Click Repair Disk.

After repairing the disk, try to start from the Mac OS X hard disk.

Tip: If your hard disk is not available (mounted) when started up from CD, reset the parameter RAM (PRAM) as described in step 3, then repeat these steps.

If your hard disk is still not available after resetting PRAM, contact an Apple Authorized Service Provider or Apple Technical Support.

Try to select your Mac OS X startup disk using either Startup Manager or the X key.

If this doesn't work, go to step 3.

Reset parameter RAM (PRAM).

Reset PRAM, then see if the computer starts up. If it doesn't, repeat step 2.

If none of these steps resolved the issue, start up from the Mac OS X Installation CD and reinstall Mac OS X. If your hard disk is not available (mounted) when started up from CD, contact an Apple Authorized Service Provider or Apple Technical Support.



Steps for Mac OS 8 and Mac OS 9

The possible causes and solutions for this symptom appear in the order that you should try them. If any step resolves the issue, you don't need to continue to the next one. If at any time in this process you determine that your System Folder or its contents are missing or were intentionally deleted, reinstall Mac OS 8 or Mac OS 9.

If you normally start up from Mac OS 9 but don't have a Mac OS 9 CD that can be used as a startup disk, follow the steps for Mac OS X above. Some computers include Mac OS X Installation CDs and a Mac OS 9 Restore CD that can't be used as a startup disk. Once you've started up from Mac OS X, make sure a copy of Mac OS 9 is installed. If you erased your disk since the last time you started up in Mac OS 9, you may need to need to install Mac OS 9 drivers.

Start the computer from the Mac OS 8 or Mac OS 9 Installation or Restore CD that came with the computer.
Open the Utilities folder and locate Disk First Aid.
Open Disk First Aid and repair the disk.
Open the Startup Disk control panel.
Choose your hard disk as the startup disk.
Restart the computer.

Note: If your hard disk is not available (mounted) when started up from CD, reset the PRAM as described below, then repeat these steps. If your hard disk is still not available after resetting PRAM, contact an Apple Authorized Service Provider or Apple Technical Support.

If you can't choose your hard disk in the Startup Disk control panel, your System Folder may have been altered or removed. In some cases, you may solve the issue by moving files back into the correct location in a process known as "reblessing" the System Folder. A "blessed" System Folder is one that is recognized as a valid startup System Folder, as indicated by the appearance of the Mac OS logo badge on the System Folder.

Reblessing the System Folder only works when all the original files are still installed and in the correct location (or you can put them back in the correct location). If any files have been deleted, you may need to reinstall system software. If you have deliberately removed System Folder files, this includes putting them back where you found them.

Additionally, you should only have one folder named "System Folder" on your disk (not to be confused with the folder named simply "System" that is installed by Mac OS X, if both systems are installed on the same disk).

To rebless your System Folder:
Start up from CD.
Close any open windows.
Open the hard disk.
Choose By Name from the View menu.
Locate the System Folder. Tip: You should only have one System Folder. If necessary, rename any other "System Folder" you're not using. Don't rename "System" if Mac OS X is also installed.
Open the System Folder. At this time, you should replace any items that you have previously removed from the System Folder, if applicable.
Do one of the following:
If Mac OS X is not installed or is installed on a different volume than Mac OS 9, drag the System suitcase and the Finder to your hard disk icon. If you have more than one hard disk, drag the files to the hard disk where the System Folder is.
If Mac OS X is installed on the same volume or partition as Mac OS 9, create a new folder outside of the System Folder but on the same disk, then drag the System suitcase and the Finder to the new folder.
Close the System Folder.
Drag the System suitcase and Finder back onto the System Folder icon.

When the Mac OS logo reappears over the System Folder, it has been reblessed. Select the folder in the Startup Disk control panel, then restart the computer.

Reset parameter RAM (PRAM)

If after resetting PRAM the computer starts up normally, reselect the startup disk in the Startup Disk control panel.

Troubleshoot SCSI (if applicable)

Improper SCSI configuration, termination, or cabling may cause this symptom.

Shut down the computer.
Turn off all connected devices.
Completely disconnect the SCSI chain from your computer. If you have installed a third-party SCSI card, take it out of the computer.
Start up the computer.

If your computer starts up OK, you know something is wrong with your SCSI chain.

Check for a conflict with recently-installed software

You may be able to start up while holding the Shift key (which temporarily disables extensions). If so, troubleshoot with the Extensions Manager.

Reinstall system software

Do this only if nothing else helps.

Mac OS X: "Broken folder" icon, prohibitory sign, or kernel panic when computer starts

Symptoms

Troubleshoot if a "broken folder" icon, prohibitory sign, or kernel panic appears when Mac OS X starts up.

This document can help when:

• A "broken folder" or prohibitory sign appears during startup.
  Note: The prohibitory sign replaces the "broken folder" in Mac OS X 10.2 or later.
   
• A kernel panic occurs during startup.
• A miscellaneous startup issue occurs.

Tip: If you're troubleshooting a different startup issue, this document can help.

Products Affected

Mac OS

Resolution

Preventing the issue

Certain Mac OS X system items or folders are invisible when started up from Mac OS X, such as "mach_kernel". But they're visible when started up from Mac OS 9 or when using software that can view or delete invisible files. Do not delete, move, or rename visible or invisible Mac OS X system files or folders. Doing so may prevent Mac OS X from starting up or working properly.

Here are examples of items from the root level of your Mac OS X startup volume that you should not delete or move:

• mach_kernel (an invisible file)
• Applications (a visible folder)
• automount (an invisible folder)
• Library (a visible folder)
• System (a visible folder)
• Users (a visible folder)

The symptoms described above can occur even when these files and folders are in their correct place.

Troubleshooting and resolving the issue

Important: Precisely follow the instructions in this document to avoid data loss or other startup issues.

Click the link that most closely matches your situation:

• Mac OS X system items appear to be normal, or you are not sure if changes took place.
• You know that you moved or renamed a Mac OS X system file or folder.

Reset NVRAM and reselect startup volume

1. Reset the NVRAM and PRAM. See Note: Resetting NVRAM/PRAM may change some system settings and preferences. For example, your volume and mouse speed settings may change. You can use System Preferences to restore preferred settings.
2. Hold the "X" key during startup. This may force the computer to start up to Mac OS X. If it does, open System Preferences and be sure that your Mac OS X System Folder is selected.
3. If the issue is resolved, stop here.

Reinstalling Mac OS X

Because you cannot install individual Mac OS X system files or folders, you need to reinstall Mac OS X. For Mac OS X 10.2 or later, you can perform an Archive and Install installation instead of an erase-installation. If the Archive and Install installation doesn't help, see erase and install below.

For Mac OS X 10.1.5 or earlier, if the version of Mac OS X installed on your computer is later than the version on your Mac OS X Install CD-ROM disc, or if you have ever installed any Mac OS X software update (including a Security Update or Installer Update), then you must back up data and perform an erase and install procedure, as described below. If the version of Mac OS X that is installed on your computer is the same as the version on your Mac OS X Install CD-ROM, and you have never installed any Mac OS X software updates (including any Security Update or Installer Update), then you may continue with this section.

Follow these steps to reinstall Mac OS X 10.1.5 or earlier:

Tip: Advanced users may wish to try the "Advanced alternative" section, below, before reinstalling.

1. Insert the Mac OS X Install CD.
2. Choose Restart from the Apple menu, then press and hold the C key immediately after the startup sound.Note: If you cannot start up from the Mac OS X CD, see "Mac OS X: Stops Responding While Starting Up From Mac OS X CD".
3. Use Disk Utility to check the disk.
4. If Disk Utility found no issues or successfully repaired any issues, then continue to the next step. If Disk Utility finds an issue that it cannot resolve, then use the erase and install procedure.
5. Start up from your Mac OS X volume.
6. If the issue is resolved, stop here. If not, continue to the next step.
7. Reinstall Mac OS X. If this does not resolve the issue, see "Mac OS X: Troubleshooting a Startup Issue".
8. If the issue remains, repeat the steps to reset NVRAM as described above.
9. Stop here. Do not continue to the next section.

Advanced alternative

This optional alternative may resolve the issue in limited circumstances in which the file "mach_kernel" needs to be replaced. It does not replace any of the other files included with a full reinstallation. The following steps should notbe used for replacing items other than "mach_kernel". If these instructions are not followed precisely, Mac OS X may not start up correctly.

Your computer has to be able to start from Mac OS 9 to use this method.

1. Start up from a Mac OS 9 CD.
2. Open the Startup Disk control panel.
3. Select the Mac OS 9 System Folder.
4. Restart the computer.
5. Eject the Mac OS 9 CD.
6. Insert the Mac OS X Install CD. A window opens showing the Installer window. Close this window.
7. Double-click the Mac OS X Install CD icon.
8. Drag the "mach_kernel" file from the top (or root) level of the CD to the top (or root) level of the Mac OS X hard disk volume.
9. Replace the existing "mach_kernel" file in that location, if prompted for confirmation.
10. Open the Startup Disk control panel, choose the Mac OS X System, and restart.
11. If this resolves the issue, stop here.
12. If the issue persists, return to the top of Reinstalling Mac OS X above.

Note: The files "mach" and "mach.sym" are automatically recreated during Mac OS X startup, if missing.

Erase and install

These steps may be appropriate if a Mac OS X 10.2 or 10.3 Archive and Install installation did not resolve the issue.

This is also the correct way to reinstall Mac OS X 10.1 when the version installed on your computer is later than the one on your Mac OS X Install CD-ROM disc. Use these steps, for example, when you have Mac OS X 10.1.4 on your computer but have a Mac OS X 10.1.2 Install disc.

Warning: Be sure to back up any files you wish to keep from the destination volume before erasing it. Because this is an extreme solution, you may wish to try the steps in Resetting NVRAM before continuing.

1. Back up important documents and data located on your Mac OS X volume. Pay special attention to the contents of the Users folder, which contains the individual Home of all the computer's users. The Users folder is located at the top (root) level of the Mac OS X disk.
2. Insert the Mac OS X Install CD.
3. Choose Restart from the Apple menu, then press and hold the C key immediately after the startup sound.
   Tip: If you cannot start up from the Mac OS X CD, see "Mac OS X: Stops Responding While Starting Up From Mac OS X CD".
    
4. If you use more than one partition or hard disk, be sure to select the Mac OS X volume from which you backed up data in Step 1.
5. Select the checkbox for "erase the target disk prior to installation".
6. Install.
7. After installation, you should reinstall any available Mac OS X software updates, reinstall applications that are not included with Mac OS X, then replace any files that you backed up in Step 1. If desired, use System Preferences to adjust settings not included in the Setup Assistant.