Hi, grammar experts

Got a question on compound nouns, particular the effect of singularity of one of/each constituent nouns in the compound noun: would the following two be different in meanings?

file-management system

files-management system

Plus, if one of these is (or both can be?) meant to describe a system that manipulates lots of files in a digital environment, then which one(s)?

The singular is used in these cases, even when it may mean something plural.
Use file management system even if the system manages more than one file (as they almost always do).
Just thought of a third option, which is quite common too:

file management system (i.e. without hyphen)
 CalifJim's reply was promoted to an answer.