When performing a clean installation of Mac OS 8.5, this error message may appear:

"Problems were encountered reading the source file "Installation Tome". Installation cannot continue."

A tome error is usually related to difficulties reading the installation disc.

1. If you encounter this error while installing software from a disk image, unmount the disk image from the desktop and try remounting the image using Disk Copy. If the image successfully mounts, try running the installer application from the mounted image once again.

2. Next, make sure the disc is clean. Clean the data side of the disc by using a dry, lint-free cloth to gently wipe the CD from the spindle hole to the outer edge. Do not wipe in a circular fashion. If you have a CD-ROM lens cleaner disc, use that to clean the drive.

If the issue persists, it may be due to an incompatible hardware. Try one or more of the following:

• Disconnect any external devices from the computer other than the display, and the Apple mouse and keyboard.
• Check to ensure that the proper RAM has been installed in the computer. Some computers require certain RAM speeds, or that RAM be installed in matching pairs. For more information, see article 20025: " Apple Memory Guide ."
• Check the internal cabling connecting SCSI or ATA devices to see if the cable has become crimped or wadded causing internal damage, or physically pierced by an internal protrusion.
• Remove any internal hardware added post-factory drives or accelerators.

Often the suspect software components can be bypassed by using alternative methods to install the software. Two alternative methods of installing the software that usually work are:

• Connect an external CD-ROM drive to the computer and use it to install the software.
• Put the disc into the CD-ROM drive of another computer that can be accessed over a network. Share the disc using File Sharing and then install the software over the network.

If difficulties persist, and you suspect the cache DIMM as a possible cause, see article 22186: " 5500/6500 L2 Cache Disable Extension: What is it? " Then contact your local Apple Authorized Service Provider for further troubleshooting.

Note: If you are attempting to install Mac OS 8.5 or later on a computer with a PowerPC upgrade card installed, you may also get this error. Mac OS version 8.5 and higher do not support PowerPC upgrade cards.