Font Swings

You’ve heard of humans having mood swings? Well, while I’m typing in my free trial period of scrivener the fonts start getting bigger and smaller without me doing anything. One second their the size I started with, then their 100 times bigger “ALL OF A SUDDEN” , then they go back to the size I started with, only today, the yfont size increased, and hasn’t gone back down. There is no change in header of the font being any bigger, and I have no idea how to “shrink” or make fonts “smaller”, any idea’s?

If this is affecting all text in the edit window, but the numeric font size displayed top center along with font name and style isn’t changing, I would guess something is triggering zooming of the view.
Can be done via View > Zoom or via keyboard shortcuts. Default values follow. Can be changed in Tools > Options > Keyboard.
Ctrl+= is Zoom In
Ctrl± is Zoom Out
Can also be set via percentage, down in the footer area if have footer view turned on (can be toggled on/off via View > Layout > Footer View).

If this was just affecting text as you type, such that text size varied within the edit window, I would look toward Format > Font, but would expect to see the numeric font size displayed top center change accordingly.
Ctrl+> is Bigger
Ctrl+< is Smaller

Beyond that, don’t know. Could be due to something external to Scrivener. Could always uninstall/redownload/reinstall Scrivener.

Are you using a laptop with a touchpad? Multi-gesture touchpads will zoom in if you have two fingers on the pad and spread them apart and zoom out if you pinch the fingers together. I use two-finger scrolling when I’m on my laptop, and after upgrading to Win10 the zooming function became a little twitchy, so that sometimes I’d be scrolling through a document and suddenly the font size would change because the laptop thought I was moving my fingers apart while I was scrolling. I had to turn pinch-to-zoom off because this was seriously messing up my workflow.

Thank you for your fast response to the question I posted, very professional. The problem seems to have been just in 1) My inexperience with “word processors”(which will continue until I’m a pro) and 2) I don’t know, maybe I was moving the mouse pad, maybe not?.., either way, after compiling(or whatever the proper name is to set all files into one file) and printing, all print “types” or “fonts” printed “equally” or without issue. Thank you again for your posted advice, insight.