Update (22nd September, 2014): Ever since I upgraded above a certain developer preview version of OS X Yosemite (DP4 or thereabouts) a couple of months ago, the problem described below has not recurred.

I've got a mid-2013 13" MacBook Air (Model Identifier: MacBookAir6,2) currently running Mavericks 10.9.2. that doesn't have any problems except (a potentially major) one: Sometimes when I'm playing a Flash video on Firefox (currently version 28.0), suddenly the screen will freeze completely - by "completely" I mean even the mouse pointer won't move. Usually the audio plays for maybe a second and two after the screen freezes before it stops too. (I'm guessing that just might be some kind of audio buffering in action.) The system goes completely unresponsive. I have to force a reboot by holding down the power key for several seconds.

This happens intermittently but frequently enough to be a cause of concern. I guess it must have happened around 3-4 times in the last month. The latest incident was last night.

I have not experienced this problem except when I'm viewing a video online. I'm running the latest version of Adobe Flash Player (which, btw, has annoyingly frequent updates) and Firefox 28.0. but it has happened with previous versions of both. I mostly view only streaming videos on this laptop - only rarely do I play a downloaded video file with a media player app, so in that respect it's hard to say whether the problem is Firefox/Flash specific or more general. But I'm pretty sure it's never happened when I wasn't viewing a video. I believe it also happened on lower versions of Mavericks.

I checked the system log in the Console app, and have not found any suspicious looking messages that could indicate what the problem could be, which makes me think it's something that happens all of a sudden - making it likely to be a hardware problem with the video subsystem. But I'm just guessing here. (There are also no log messages generated after the time of the freeze until I force a reboot, which would indicate that the system has in fact completely halted, rather than a case of unresponsive UI.)

I have run "Apple Diagnostics" more than once and it reported no issues.

How can I diagnose this problem? Is there a more severe battery of hardware tests that I can run? Or should I look into using DTrace?

  • I do not know how experienced you are in reading the console log, but publishing it here around the time stamp of the event could lead to something.
    – Ruskes
    Apr 23, 2014 at 10:50
  • I am using Firefox exclusively and for all Videos, newer had any problems with it. I also have a MBA mid 2012 with 10.9.2. So maybe you publish the link so I can try it.
    – Ruskes
    Apr 23, 2014 at 10:55
  • @Buscar웃 while I don't claim to be an expert at reading the console logs, but when I looked at events around the crash time, I did not see anything out of the ordinary - the messages I saw were to do with apps running in the background I recognise (nvAlt, Preview, iTunes, etc.) and the same messages are peppered throughout the logs. The main thing is I wasn't able to detect any obvious correlation between the logs for two different crashes - like if the same message(s) had popped up right before each crash, that would've been telling. But I found nothing of the sort.
    – Aky
    Apr 23, 2014 at 16:27
  • That said, I could've missed something, so next time it happens I'll keep a copy of the action before the crash happens.
    – Aky
    Apr 23, 2014 at 16:28
  • Ok, what is the link it happens on? so I can try it.
    – Ruskes
    Apr 23, 2014 at 18:17

3 Answers 3


Sounds like bad sectors on the harddisc/SSD. I have had similar experience. My Macbook air 2012 froze when I was playing music, everything else worked fine, then one day it totally stopped working (lookup Mac OSX grey folder for more information). I went it by the Apple store and they replaced my SSD.

  • Interesting; I've had problems due to bad sectors in my (magnetic) hard disk on my previous MBP (IIRC there's a thread of mine on this very forum on that issue.) My current laptop has an SSD though, but I have absolutely no idea how the system responds to bad "sectors"(?) in an SSD.
    – Aky
    Apr 23, 2014 at 16:34
  • @Aky Yeah I dont know if a SSD can have bad sectors, but something was wrong with my disc and worked not well in some weeks before it totally was gone (grey folder).
    – JW_
    Apr 23, 2014 at 16:52

I experience this problem. FF was 28, now it's 29, Flash plugin version is 13.0.r0, Console logs are clean, I mean there are no any records for minutes before BOOT_TIME marker. Tried to reinstall Adobe Flash,check disk using Disk Utility, disable all browser extensions. Definitely, it's not a hardware problem because I can't reproduce it using another browser.

  • I'm observing the same thing in my logs.
    – Aky
    Jun 19, 2014 at 13:52

There a few hardware issues that could cause your problem (ram, drive/SSD) but there are MANY software issues that could cause it. It helps to first prove which it is.

If you boot that computer by another hard drive, you can test whether the issue is hardware or software. Once you have that answer, you can proceed to the next step.

You do have an external hard drive with an appropriate OS and all of your fix-it utilities on it, don't you? :D

No? Maybe it's time to make one!

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .