You can make a difference in the Apple Support Community!

When you sign up with your Apple Account, you can provide valuable feedback to other community members by upvoting helpful replies and User Tips.

Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

davidnave Author

Level 1

10 points

When waking Macbook Air 2012 from the Login Screen, the display flashes, then works normally. Mildly concerned.

I have only noticed this behavior when no users are logged in, and the computer is put to sleep by closing the clamshell. It also only appears to happen after an extended sleep, meaning 30 minutes or more. I open the clamshell, the backlight comes on, I see the login screen, then the screen flashes like when Photo Booth takes a picture, then the computer works normally. This is not a great concern, but it is unusual. It doesn't happen when a user is logged in. It doesn't happen during boot. I am running 10.8.2, and do have power nap enabled. I have noticed the behavior both when running on the power adapter and on the battery. No Accessibility functions enabled. Trying to isolate the issue, and reaching out for others with same behavior. Cheers.

MacBook Air, OS X Mountain Lion (10.8.2)

Posted on Sep 20, 2012 7:45 AM

Top-ranking reply

Jon P D

Level 4

1,522 points

Posted on Sep 20, 2012 11:25 AM

the screen flashes like when Photo Booth takes a picture

Do you have any security software installed? Some have features that take a photo with the webcam when the lid is opened.

View in context

72 replies

Oct 27, 2012 12:50 AM in response to davidnave

Getting the same problem. Have reset the PRAM too, as thought that might work, but had no effect. Have just tried turning off mirroring to see if that works.

Oct 27, 2012 8:39 PM in response to davidnave

Had same issue here, after enabling power nap con battery mode, screen flashes 2 times when opening the lid.

Disabled it and now works ok. A very annoying bug.

RRFS

Level 5

4,522 points

Oct 27, 2012 10:21 PM in response to davidnave

Run

OnyX for Mac

http://www.macupdate.com/app/mac/11582/onyx

http://helpdesk.hsc.unt.edu/wp-content/uploads/2010/02/Mac-OS-X-10.6-run-OnyX.pd f

slamj

Level 1

4 points

Nov 4, 2012 9:59 PM in response to RRFS

I have tried everything, and am still have the issue with the screen flashing brightly twice after waking the Air from sleep. It seems to be a hardware issue with Mountain Lion. Anyone fix this issue? I have tried all suggestions within this post.

bloodnok

Level 1

1 points

Nov 5, 2012 9:05 AM in response to davidnave

not just macbook air afflicted with this. my 13" retina macbook pro has it, too. it's some sort of bug introduced in 10.8.2.

along with that, mountain lion takes far too long to enable the login prompt from sleep - upwards of 30sec in some cases. too many times, i've ended up with just the end of my password entered and the shivered you got it wrong response from the o/s. this happens on my imac, my macbook pro, and happened on my retired macbook air. the corollary to that is when putting the imac to sleep, it can take over 30sec for it to be effective. this is new in 10.8.2. 10.8.0 was slow to wake. the latest updates have made its behaviour worse.

well tested, apple!

davidnave Author

Level 1

10 points

Nov 6, 2012 11:48 AM in response to davidnave

Some new information. I noticed that when opening the clamshell after a long sleep, the login screen is there, but the cursor will not move for several seconds. I have noticed with a lot of the Mountain Lion Macs I work with. But on the Air, the screen flashes before the the cursor will start tracking. Also, a couple times, I get the bluetooth mouse setup assistant window right before the screen flashes. The Air has a built in trackpad, which should always be detected. Think this is related.

NickH2

Level 1

5 points

Nov 6, 2012 4:45 PM in response to davidnave

I had the same problem with my mid 2009 MacBook Air after the latest Moutain Lion 10.8.2 upgrade but it seems to have been solved for me by:

(a) Enabling the Power Nap (it was off) in Enery Saver -> Battery

(b) Unchecking the "Show mirroring options in the menu bar" in Display

("Automatically adjust brigthness" is turned on on my MBA)

I have tested various combinations of sleep/restart/log-out with lid closed and then opening it and I don't get the flicker any more.

It could be a long-term rather than short-term problem as others have commented so will continue to monitor (sorry - bad pun!)

davidnave Author

Level 1

10 points

Nov 6, 2012 5:40 PM in response to NickH2

Looks like a good combo to try. I will try it as well. Keep us updated.

mushu637

Level 1

0 points

Nov 8, 2012 9:13 AM in response to NickH2

(a) Enabling the Power Nap (it was off) in Enery Saver -> Battery

(b) Unchecking the "Show mirroring options in the menu bar" in Display

("Automatically adjust brigthness" is turned on on my MBA)

didn't help... The problem is still there (((( MCA 13" mid 2011

Apparently it's flashes only on battery power... if you plug in power before opening the lid, it's logs in normally...

the other thing I notice, it flashes if network changes... i worked in the morning at home, closed the lid, open at work and it flashes... and same thing in the evening... Apple support didn't help, and had no idea what it could be... to me it is obvious bug in Mountain lion... hope Cupertino gyus are monitoring this...

Nov 10, 2012 12:55 AM in response to clever_trevor

That's exactly what I have. Thought it was something to do with me trying to partition my drive to run Ubuntu & OS X, so deleted the Ubuntu partition - but still it flashes. Very odd.

davidnave Author

Level 1

10 points

Nov 17, 2012 8:33 AM in response to davidnave

Does anyone have Dropbox, GoogleDrive running? Also, does anyone have iCloud's Back to My Mac enabled? I am frequently seeing a loginwindow error 1102 in Console, relating to Get Screen Sharing Port.

Nov 19, 2012 9:36 AM in response to davidnave

Same flash issue when waking up 13" MBA (2012) after sleep on battery. Showed up after 10.8.2 update. Very annoying. Before I noticed the flash, it would lock out the mouse/keyboard input for a few seconds so I couldn't type in my password. Now, the last few days, it does that, then flashes white before becoming usable. This is a brand new machine with a fresh, clean install of Mountain Lion. Very frustrating, but I'm glad to see it's probably not hardware based, due to the other comments in this thread.

davidnave Author

Level 1

10 points

Dec 10, 2012 12:44 PM in response to davidnave

Update. I removed a file at the root level of the harddrive that was larger than it was supposed to be. It was located at /private/var/vm/ and called "sleepimage". It should be exactly the same size as the system memory (RAM), but mine was almost twice as large. I deleted the file, then restarted. The system will recreate that file the next time you put the computer to sleep. I have not had the flashing issue since. Crossing fingers.

Dec 10, 2012 7:23 PM in response to davidnave

My flashing went away, but I've still got a delayed log-in screen; it shows up but doesn't let me enter anything for a good five seconds, plus the screen is dimmed.

da-cam

Level 1

0 points

Dec 12, 2012 9:25 AM in response to klockw243

Davidnave's suggestion seems to be the best one so far. Since deleting the file, my MBA has stopped flashing (which had gotten much worse in the past week before trying the fix. I am not experiencing the delayed lon-in sceen either.

When waking Macbook Air 2012 from the Login Screen, the display flashes, then works normally. Mildly concerned.