Recently my mac has been mysteriously logging itself out whenever I attempt to launch any resource-intensive programs, such as games (roblox) and 3D applications. I have looked at many solutions to similar problems online, such as resetting PRAM and NVRAM, and have even gone so far as to reinstall MacOS. Yet the problem persists. When I open said applications, they work for about 2-3 minutes and then suddenly freeze before the screen goes black and a small loading icon appears and then it takes me to the login screen.

Does anyone have any idea what could be going on?

Whenever it crashes, files such as this pop up in /Library/Logs/DiagnosticsReports


And the content:

enter image description here

That's what I get when it crashes with blender, but I'm also getting some WindowServer logs too. enter image description here

  • Firstly, welcome to Ask Different! :) Can I ask you to please edit your question to include your model of iMac? I have some suspicions as to what's going on, but knowing your hardware details will help.
    – Monomeeth
    Oct 27, 2019 at 22:13
  • A guess would be OpenGL issues - possibly memory. If you are running 2 apps that use OpenGL, they don't share very well. Photoshop etc is also bad for this if running alongside games. If you can check with the game maker for how to reduce OpenGL memory [or check that's in fact what the game uses] & report back.
    – Tetsujin
    Oct 27, 2019 at 23:11
  • Have you checked if heat could be an issue? Oct 29, 2019 at 0:34
  • The fan doesn't appear to be ramping up, and the hardware check says it's okay. Oct 29, 2019 at 14:29

1 Answer 1


The cause for your issue is most likely related to the graphics processing unit (GPU) of your iMac. This is what's commonly referred to as a graphics card.

Some games and applications will place the GPU under a much heavier load compared to others.

For example, using a word processor will not tax the GPU much at all, but using applications such as Photoshop, Maya, Render, Final Cut Pro, Motion, etc will place a much heavier burden on the GPU. I'm not familiar with Roblox, but it's likely that it's also taxing the GPU heavily.

Normally this would not be a problem, but if your Mac has a GPU that has developed a problem, it'll be enough to effectively cause it to crash in such a way that your Mac has to reboot. In this scenario it's a hardware fault that may mean repairing or replacing the GPU.

Some Mac models were more prone than others to these types of problems. For example, the 27" iMac model from mid-2011 was the subject of a graphics card replacement program for exactly this type of issue.

However, it doesn't necessarily have to be a hardware fault. Software can often cause problems. For example, it could be a conflict between software, drivers, etc or a lack of graphics memory (especially if running multiple apps simultaneously). You could try troubleshooting this further by only running one application and seeing what happens. Perhaps testing in Safe Mode may be an option as well.

Remove any CUDA and NVIDIA drivers

Since you're running macOS Mojave (or above), you should be aware that any CUDA and NVIDIA drivers you have installed aren't supported.

To remove these:

  1. Launch Terminal (found within your Utilities folder)
  2. Copy and paste the following commands, one by one, into Terminal followed by pressing enter on your keyboard. Each time you do this you'll also have to enter your Admin password.

    • sudo rm -rf /Library/Extensions/CUDA.kext
    • sudo rm -rf /Library/Frameworks/CUDA.framework
    • sudo rm -rf /Library/LaunchAgents/com.nvidia.CUDASoftwareUpdate.plist
    • sudo rm -rf /System/Library/StartupItems/CUDA
    • sudo rm -rf /usr/local/cuda
  3. Go to Apple > System Preferences

  4. Right-click on the CUDA preference pane
  5. Select the Remove "CUDA" preference pane option

OPTIONAL: If you also have NVIDIA Web Drivers installed (that's a 'yes' if you have the NVIDIA icon in the menu bar), then follow these additional steps:

  1. Still in System Preferences, click the NVIDIA Driver Manager preference pane
  2. Select the Graphics Drivers tab
  3. Click on the padlock and type your password
  4. Click the Open Uninstaller button
  5. Click Uninstall
  6. Complete the Uninstall process and restart your iMac
  • Hi, thanks for helping me out! If it's any help now, I'm using a 27-inch, Late 2013 iMac with a NVIDIA GeForce GT 755M. I'll update the CUDA drivers (something I haven't done in a while). I did try running just one application and it still causes this problem. Oct 28, 2019 at 11:11
  • Well, it hasn't solved the problem. I install Catalina and installed the latest CUDA updates but it's still doing it. One thing I've also noticed is that the speed has also deteriorated too. It happened pretty suddenly last Saturday afternoon and since then has been really slow. Oct 28, 2019 at 14:24
  • Ah rip, it's just done it again without any applications open aside from finder. I'm not sure what to do now. Oct 28, 2019 at 14:25
  • I'm currently in safe mode and some funky stuff is happening. Typing this message is quite weird because I can only see half of the text, the top half is cut off, the google 'New tab' page is doing some funny things too, and Blender (My 3D application) and all that happens is a message that pops up saying that blender has quit unexpectedly. Oct 28, 2019 at 14:55
  • Sorry for the ridiculous amount of updates, but I did the apple hardware check and that didn't reveal anything, which leads me to hope that it's just a solvable software problem. Oct 28, 2019 at 15:31

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