why does my screen keep dimming on its own?

Go to System Preferences > Displays > Uncheck "Automatically adjust brightness."

Do a SMC reset frist then if all else fails the Apple Store is where you need to go.

mindwarJul 18, 2014 7:49 PM
Re: why does my screen keep dimming on its own?in response to Kaygen1

Go to System Preferences > Displays > Uncheck "Automatically adjust brightness."

THANK YOU!!! my computer went rogue. Dimness going up and down, up and down. Unchecking that box fixed it!

Check your System Preferences > Energy Saver and ScreenSaver preferences, install the free Caffine.

http://www.macupdate.com/app/mac/24120/caffeine

10.8 users may have to set System Preferences > Security > General downloads to "anywhere"

The screen dims when it thinks it is "low light" conditions. When you "shadow" the light sensor beside the microphone at the top of the screen (either by partially closing the lid or by moving your body) it thinks "dark ... turn on keyboar lght and dim screen".

For me, at least.

If you stop working it will go to energy save and dim, or background light can change and cause the light sensor to change the brightness. Check System Preferences > energy saver for the settings and if dimming is set for too short a time change it to what you would prefer.

If the lighting is constant, the energy saver setting is ok, and it is auto dimming for no reason, try a restart and see if that clears any glitches, then it might be worth a trip to the Apple store genius bar to have the techs run their diagnostics.

OK this is what worked so far on my phone

i used to use the 30 second auto lock

i changed my auto lock to 2 minutes and so far no more dimming

it may be a software glitch in the 30 second auto lock feature

Mindwar, you saved my sanity! Displays and uncheck fixed it!

Thank you mindwar! This was driving me nuts for weeks!

Perfect, and so easy! Thank you so much Mindwar!!