What Does Molly-Guard Mean?
A molly-guard is a physical shield or barrier that prevents unauthorized or improper access to part of a hardware device. The molly-guard is placed over a button, lever or other control so that less experienced users have more trouble getting to it and it cannot be activated by accident.
Techopedia Explains Molly-Guard
In the urban legends surrounding this term, “molly-guard” is
often attributed to a programmer working on an IBM 4341 mainframe computer.
According to the story, the programmer's young daughter, who was named Molly, pushed a particularly important control button twice during a given day. Presumably, the
programmer then constructed some type of molly-guard to prevent further
As the term has emerged, it has often been used in conjunction with
the term “big red switch” for a primary power switch, shutdown switch or other primary
control, and may be used on hardware devices or even on industrial machinery.