System 3.1

System 3.1 was released in February 1986, a month after System 3.0, along with Finder version 5.2 as part of Macintosh Printer Installation version 1.0.

It had serious flaws impacting file storage and system stability. Use of System 3.1 was seriously discouraged, and use of 3.0 was encouraged until 3.1 was replaced by System 3.2 four months later.