I have read this question and tried to follow the selected answer's advice. I have also read this question but the second question I believe is unrelated to my issue. (But I'm not sure.)

When Ubuntu (Or possibly just Unity) crashes everything stops working. I have to completely turn the machine on and off. I cannot do the SysReq soft-reboot because I have not been able to find a key-equivalent for my keyboard/laptop model.

I can provide logs upon request, but to be honest I don't know which ones would be of use, or how much of those logs would be of use.

My computer is a Dell Inspiron 11 3000 series. I believe this is my model, assumed after cross-checking system specs with the listing I linked. The PC is running the newest LTS release of Ubuntu 14.04 Trusty Tahr.

At first I believed this to be a problem that only occurred during video playback, but while the system doesn't crash near as often when not playing back video, it still will occasionally.

I'm a software engineer, so I HAVE to have a reliable computer. I've recently decided to open-source all of my company's non-client-specific code, and changed all of my servers to Debian, and also installed Ubuntu on my main workstation. The company now uses 100% open source software on all of its machines. However, I will be forced to return to Windows if I can't resolve this issue, and I would really be bummed about that.

  1. What are the steps, in plain language for an Ubuntu novice, of diagnosing crashes on Ubuntu?
  2. Once discovered, what resources can I use to fix these issues?
  3. And finally, is there a chance that I will be forced to use proprietary software in order to correct these issues?


  • "And finally, is there a chance that I will be forced to use proprietary software in order to correct these issues?" If you really have Intel HD graphics (and not hybrid NVIDIA/Intel graphics), probably no, as the official Intel drivers are open-source (Intel is smart that way). Mar 9, 2016 at 22:43
  • When you first installed Ubuntu, what exact version did you install? Mar 9, 2016 at 22:51
  • If it was 14.04.1 or earlier (not 14.04.2 or higher) try running the command here: askubuntu.com/questions/740690/… Mar 9, 2016 at 22:56
  • I'm running Ubuntu 14.04.4.
    – Allenph
    Mar 9, 2016 at 22:57
  • Is that the version you first installed or the version you are running now? Mar 9, 2016 at 22:59

3 Answers 3


Not enough technical details are provided here and only suggestions can be made.

First you have to determine if its a Operating System issue due to installation/configuration errors or a Hardware failure due to faulty hardware.


In the first case you could check the System logs try:

  • Check /var/log/ in terminal:

    sudo nano /var/log/syslog
  • If you are running GNOME, then you can check with a GUI all logs using "gnome-system-log" tool, type:


    if it's not installed, type:

    sudo apt-get install gnome-system-log
  • Also try replicate the issue by booting in recovery mode, or try another OS environment or another installation, or ssh into the system to see if it happens. If it occurs its likely a hardware problem if not, look for clues in OS logs.


If it's a hardware fault and after you have checked that the RAM, HDD, CPU temp are OK. I suggest you call a tech support, even better if you're still in warranty.

Reminds me a similar problem that I had once with lots of random crashing although the Ubuntu system seems to be randomly "OK" just to discover it was due to faulty RAM.

It seems like a Memory hardware issue here and memory problems can be hard to detect. If you haven't checked on them yet.

One way to diagnose this and check your RAM is with an application Memory Test. You usually find it on the boot menu from your Ubuntu LiveCD or any other live CD with a memtest application on it. Once the Boot menu appears you will see the option for Checking you Memory RAM choose: [Test Memory] or [MemTest86+].

If you do have a bad memory, you will get at least one RED row on the bottom half of the window application. Also I suggest to test each memory individually and to different slots if you don't find a memory error with both installed. This way you will definitely know if one memory is defective.

  • Ran a test with a Live USB of Ubuntu 14.04 today. No errors.
    – Allenph
    Mar 15, 2016 at 6:47
  • @Allenph have you tried to run it with some other compatible memories?
    – Denja
    Mar 15, 2016 at 19:44
  • I don't have any, unfortunately.
    – Allenph
    Mar 15, 2016 at 23:48

I suspect your GPU is overheating. Let's check your temperatures.

sudo apt-get update
sudo apt-get install psensor

Please post screenshots of your temps.


on Unbuntu 22.04

with random crashing, same as above, ...

<short answer>
turn off Intel-VT in your bios settings

<long answer>

tail -n 25 /var/log/syslog showed:

kernel: [  551.300388] DMAR: DRHD: handling fault status reg 2
kernel: [  551.300402] DMAR: [INTR-REMAP] Request device [03:00.0] fault index 18 [fault reason 38] Blocked an interrupt request due to source-id verification failure

Found several manufacturer articles (e.g. Lenovo, HP) blaming DMA contention between threads when Intel-VT was enabled on Ubuntu.

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