Can I again (mentioned at various times over the years) point out the confusion due to wording of these options?
The problem is the inconsistent meaning of "Tags", which really has no solid meaning at all. In MC, Tags generally means metadata, but there are two places such data exists: Database and File. Saying "Tags" doesn't make clear which is which.
"Update tags when file info changes" means (presumably) "Update Library when File info changes" (of "Update Library when File metadata changes").
"Update Tags (from Library)" means (presumably) Update File info from Library"
The first "Tags" refers to Database fields. The second "Tags" refers to File fields. Sure, the meaning can be worked out from context, but why not simply say it clearly?
Also (while I'm ranting), "Library" is not crystal-clear either. In MC it generally means the Database rather than Files. But users often refer to their collection of Files as their Library. MC's Database catalogs, manages and uses the Files that comprise the Library, but is it actually the Library? Or is that the Files?
Why I have these opinions: I used to write documentation and books on tech, design and develop, apps, write IT white papers (mainly for IBM) to explain stuff, etc, so I hope my comments are food for thought. Making things clearer and more consistent is the best way for newbies to become successful, happy customers.