Snapping not working at all I can't get vertex/edge/face snapping (or even grid snapping) to work in one blender file. I have tried this file in 2.79 and 2.79a. If I open another .blend file snapping works fine.

I have saved/closed/reopened the file, restarted Blender and rebooted the computer and upgraded Blender, all to no avail.
Well, I compared with another file, setting-for-setting, until I found the answer. It turns out that in the 3d-view header (in edit mode) there is a button for "Proportional Editing Mode", and when I set that to "disabled" then snapping started working again. I have no idea what I did to enable that (probably accidentally pressed some obscure key combo). I searched all over the Interweb for this issue and although I found a bunch of folks with the problem, nobody offered this "solution". I hope this helps the next poor soul that has this issue.