10 Replies Latest reply: Dec 12, 2015 3:59 PM by rochefel Branched to a new discussion.
Pier Rodelon Level 1 (25 points)

Working on a mid-2011 MBA 13" 128GB machine I notice what appears to be a fluctuation in the screen brightness. It's periodic, and could be my imagination, but I'll be sitting here typing a msg (as into this blank box) and there seems to be a surge and then a etracement in the overall brightness of the screen, the whole change taking maybe 2 seconds, maybe less.  It's a gradual all-over brightening followed by a decrease in brightness to what I assume was the original.


Has anyone else seen this or anything like it? It's fairly subtle, which is why I wonder if I'm seeing it at all.



  • markfromwillaston Level 1 (100 points)

    Is it the automatic brightness adjustment kicking in? If there is a change in the brightness of the room (sun goes behind a cloud - that kind of thing) the screen will try and compensate.


    Does it still seem to be happening if you switch off auto brightness adjustment? (System Preferences->Displays)

    If the problem goes away then consider keeping it switched off.

  • Dave Nikkel Level 1 (0 points)

    I am experiencing the same problem.  In fact, yesterday, it was extremely annoying.  I was getting quite extreme changes in brightness and it was fluctuating almost constantly.  Extremely annoying.  The ambient light situation was not changing at all, totally static.  However, I was sitting beside a window and it was pretty bright outside. Today, the problem is not happening or at least, it's suble enough that it's not bugging me.

  • misdirected baggage Level 1 (0 points)

    Did anyone solve this?  I'm encountering the same thing and it's very annoying.  I'm in a closed room with no light variations.  But the machine behaves as if the ambient light is varying considerably and randomly. 

  • dstaten Level 1 (0 points)

    Mark has the correct solution. Why are people still missing this?


    Go to System Preferences -> Displays and then uncheck the box about autoadjusting brightness. That's it.

  • leibie101 Level 1 (0 points)

    No, that's not the solution (at least for me). I have unchecked the box for auto-adjusting. My screen brightness keeps fluctuating. I have the Preference Panel open with slider visible while I'm working on the plane, and I can literally see the slider moving up and down periodically. It is adjusting itself for some reason when the Preference is set not to adjust itself. Highly annoying! Any other suggestions out there?

  • misdirected baggage Level 1 (0 points)

    ... Duh....that's because Mark's (very obvious) solution doesn't solve the problem.  There may be issues with certain environments (eg, aircraft, temperature) that seem to aggrevate this issue.  My only solution was to run the battery to zero, recharge and restart.  That seemed to bring things back to an equilibrium, but that's hardly a solution.

  • jeffersrox Level 1 (0 points)

    I noticed this happened everytime my body/head cast a shadow on my screen or keyboard, even though the lights in the room were pretty constant. I figured this out because my keyboard lights kept flickering on and off too. So i just switched off the auto light adjustment for both the keyboard and display and now its all fine.

  • William Mclaughlin Level 1 (0 points)

    I see this thread -- although old -- remains not-quite-resolved.


    I happened across it this morning while researching my own MacBook Air's spookily fluctuating display brightness levels.


    Eventually, i moved on to another issue, which had made itself far more pressing:  the fact that my MacBook wasn't charging.  Stepping through the Support page to here:




    ...i clicked to here:




    Following that page's instructions to, "Unplug the MagSafe power adapter from the Mac and the wall power socket for several seconds .... Shutdown the Mac. Physically remove and re-insert the battery (if it's removable) and startup the Mac," my MacBook Air seems to be charging alright now.


    I continued reading through the article, and that's when i learned that the fluctuating display brightness may actually be an "Indicator" that a System Management Controller (SMC) reset may be necessary ... or, in my case, can be averted by removing the power adapter, shutting down, and starting up.


    I hope that anyone who happens across this thread -- as i did this morning -- might find my (accidental) research helpful.

  • PlotinusVeritas Level 6 (14,725 points)

    its not as OLD at the thread youre responding to.



    which is 3 years old.

  • rochefel Level 1 (0 points)

    You could just go to System Preferences > Display. Then, you'll see this box and un-check the box where is says "Automatically adjust brightness".

    Screen Shot 2015-12-13 at 7.png