Mac OS X 10.0: Classic Does Not Work From a UFS Disk on First Use

When Mac OS X 10.0 is installed on a disk or disk partition that uses the UNIX File System (UFS) format, use the steps in this article to open the Classic environment for the first time.
Symptom

The Classic environment does not open.


Solution

To use Classic, you must already have Mac OS 9.1 installed on a separate volume that uses the Mac OS Extended (HFS Plus) format. This issue is resolved in Mac OS X 10.1 and later.

For affected Mac OS X versions, follow these steps to open the Classic application for the first time:

Note: You only need to open Classic from the HFS Plus volume the first time that you use it with a specific Mac OS 9.1 System Folder. This allows Classic to install required components into the Mac OS 9.1 System Folder. Classic opens normally from the original copy on the UFS volume on subsequent use. If you change the Classic startup volume or remove the components installed by Classic, you must open the copy of Classic that you have installed on the HFS Plus volume.
Published Date: Oct 7, 2016