My login screen has all of a sudden become zoomed in. But once I'm logged in, the screen size/zoom is back to normal. What is going on here?
MacBook Pro with Retina display, OS X Yosemite (10.10.1)
Ok, solved it by resetting the PRAM (ALT+CMD+P+R while booting, you can find detailed steps anywhere on the interwebs)
I believe the resolution changed, so it wasn't a "zoom" issue afterall.
When you are in your startup/logon screen (the screen where you type your password) try pressing ALT+CMD+F5 (you might have to press Fn too to get to F5 instead of the keyboard-light button). You'll be presented with all sorts of accessibility options, one of the first ones is the zoom function. But it doesn't seem active, because the zoom-slider is already on its lowest value.
Anyway, clearing the PRAM should fix your issue.
I have the same issue. Must be some kind of key combination, while I was cleaning my keyboard.
Tried most of the keyboard combinations along with any combination of the CTRL, ALT and CMD keys, but to no aval.
I did discover however that you can control the contrast of the login screen with the key combination CTRL+ALT+CMD and then ? or . (Belgian AZERTY keyboard here)
my login screen is now zoomed in and I cannot change it.
