My Mac Won't Start Up After I Connect a Drive to It

After I connect a SCSI drive to my Mac, it won't start up.

Every SCSI device on each SCSI bus must have a unique SCSI ID on that bus; SCSI devices can have an ID number between zero and seven. When you connect a SCSI device that has the same SCSI ID number as a device currently on the same SCSI bus, your Mac will be unable to start. Do the following:

  1. Remove the drive from your Mac.

  2. Launch System Profiler and click the SCSI tab.

  3. Check the device numbers of the SCSI devices on the bus to which you are attaching the drive; there might be more than one SCSI bus, so make sure you are looking at the right one.


    Make sure you power down all devices before changing the SCSI ID.

  4. Reset the SCSI ID to an unused number between zero and seven.

  5. Reattach the drive and start up your Mac.

If the Mac restarts, you can initialize the drive.

If your Mac still won't restart, the drive you have attached has not been properly terminated. Check the manual that came with the drive to see how to terminate it. If the drive is not self-terminating, you have to add a SCSI terminating cable to it.

Disk Utility Can't See My Drive

When I launch Disk Utility, it does not recognize the drive I installed.

The fundamental problem is that your new drive is not registering with your Mac. There can be many causes for this problem, but the most likely are the following:

  • The drive is incompatible with your Mac? Double-check the drive's specifications against those in your Mac's owner's manual.

  • The drive is improperly installed? Repeat the installation steps to ensure that the drive is installed and connected properly.

  • An internal drive is not set to be the slave? You must set any additional drive to be the slave; your Mac's "first" preinstalled drive must be the primary drive. See the instructions that came with your drive to see how to set it as the slave.


Different Mac configurations might require slightly different configurations of drives. Check the user's manual for your Mac before installing an internal drive.

I Can't Create a CD

When I try to create a CD, the CD-RW drive can't be found or the process is never completed.

Creating CDs can be a finicky process.

One complexity associated with using CD-burning software is that these applications support only specific CD-RW drives. If a particular drive isn't supported by the application you want to use, it won't work. Your only option is to find a version that will support your drive or find another application that will.

CD-burning applications can also interfere with one another. If you have more than one CD-burning application installed on your Mac and have trouble creating CDs, remove all the applications but one.

You can also have data transfer speed problems. Most CD-RW drives include a buffer to which data is written before it is placed on the CD. This buffer ensures that a steady stream of data is written to the CD. If this stream is interrupted and the buffer becomes empty, the process will fail or it will appear to finish, but the CD will be unusable. If this happens, make sure no other applications are running before you attempt to create CDs.

    Part I: Mac OS X: Exploring the Core
    Part III: Mac OS X: Living the Digital Life