Mac OS 9: Update Does Not Install, "cannot read file in.img or help.img" Alert Boxes Appear

Symptom

While installing a Mac OS 9 update over an existing System Folder, an alert box appears with one of the following messages:

• "cannot read file in.img"
• "cannot read file help.img"

Solution

Note: A disk image volume has an icon that looks like a disk and a filename without any extensions. It behaves like a disk. A disk image file has an icon that looks like a file (a paper with a dog-eared corner) and a filename extension of ".smi" or ".img".

1. Drag the icon of the updater disk image volume to the Trash. Important: This icon's filename does not have an extension such as ".smi" or ".img".
2. Double-click the disk image file of the Mac OS 9 update icon whose filename has a ".smi" or ".img" extension. A new disk image volume icon appears on the desktop.
3. Open the disk image volume, and install the update.

For additional information on this issue, consult the "ShrinkWrap or ShrinkWrap engine reports an error" section of technical document 75098 "Software Downloads: Software Format and Assistance".