Twentieth Anniversary Macintosh, Mac OS 9.1: Updating Mac OS Disables Virtual Memory

Updating to Mac OS 9.1 on a Twentieth Anniversary Macintosh disables virtual memory.
Symptom

Installing Mac OS 9.1 on a Twentieth Anniversary Macintosh disables virtual memory. Alert boxes may appear with messages stating that you do not have enough available memory to perform certain tasks.

Products Affected

Solution

Note: Virtual memory defaults to one megabyte more than the actual amount of memory (RAM) installed in the computer (for example, 65 MB on a computer with 64 MB of physical RAM). Some applications may require that you increase the amount of virtual memory. Total virtual memory is the combination of the computer's physical RAM and space designated on the computer's hard disk for use as "virtual" RAM. As reliance on hard disk space for virtual memory increases, system performance may decrease depending on application. For best performance, add additional physical RAM.
Published Date: Feb 17, 2012