System 3.1

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

Issues
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.