Hard Freeze Almost Every Flight

I have been having hard freezes that require a PC restart on almost every flight recently. The whole PC just completely locks up usually at 2-2.5 hrs, and I have to restart. I will make some changes, and have a successful test flight of ~4 hrs, and then try another flight and it’ll freeze again.

I’m using the PMDG737, AIG traffic, no Offline AI Traffic, LittleNavMap, Navigraph, TOPCAT. Plus I have about 10 add-on airports.

I’ve tried various steps: removing all except PMDG737 from Community folder, then adding back slowly doing test flights, etc to try to nail it down. Even reinstalled MSFS. I also upgraded NVIDIA drivers to latest version.

It’s not a CTD. It’s a HARD lockup, and that seems more concerning than just a CTD, as I’m wondering if it’s a hardware issue of some kind. I’ve run a hardware monitor on several flights, and nothing seems wrong at the time of the lockup: temps and load are not unusual.

This seemed to just start ~2 weeks ago; for the life of me, I don’t know what changed. I’m wondering about underclocking my CPU/GPU. Or maybe rolling back to a older NVIDIA driver, but I don’t know if it’s even a GPU issue. Ugh.

Any help appreciated.
i9-9900K; 32 GB RAM, RTX3080. Nothing is overclocked. RAM XMP is OFF.


Explain the freeze. No input to any switch/button. No animations, no yoke throttle movements? You can still hear engines running. Doesn’t advance in position on the map. Have you loaded in dev mode and seen if/when this happens that it is possible to unpause using the dev mode feature? Just options.

Thanks for this. The entire PC is completely frozen, including Windows. Mouse pointer disappears, no input from anything (keyboard, joysticks, mouse). Sound either goes silent, or goes into a constant static-like sound. I had it in dev mode several times during my testing, but again it’s completely locked/frozen, so I can’t do anything at all, other than holding the PC power button to shutoff the PC. It’s perplexing.

I went from occasional CTD 1 month ago, to what felt like more frequent CTDs, and then these hard freeze/lockups started. I’m at a loss. Just played RDR2 for an hour or so, with no issues.

Feel like I need to stress test my CPU/GPU, but am struggling to find an app that is free for stressing the GPU (I have CPU-Z for the CPU stress test).

Try OCCT, it works both for CPU and GPU. https://www.ocbase.com/
An alternative for the GPU only is Furmark. FurMark > Home
Your issues are most probably caused by hardware. I have been performing many 3 hour flights and even an 8.5 hour flight in the last days and the sim is rock stable.

Regarding stress test, testing both at the same time is also a must, you should be able to utterly hammer both CPU and GPU 100% at the same time as FS does this to an extent.

OCCT is pretty good for detecting VRAM errors on GPU’s (I use it), actual stress test, just grab 3dmark and let it loop.

Furmark basically just tests power draw, it drops the clocks right down, card hardly even gets hot.

If you want to test CPU stability quickly, and reliably, use intelburntest, set it to high and let it run.

Check that all your windows system files are up to date. What was the last thing you installed prior to having the lockup/freeze? The common connection between navigraph and little navmap and the sim is simconnect. Use your windows Task Manager to see what is running at high process when your lockup occurs. Hopefully that will give you some insight to what might be the issue. It’s frustrating to do forensic diagnostics when all you want to do is have an enjoyable flight. Been there and still do that.

Good advice thanks!

So, at this point, I’m back to systematic troubleshooting. I have determined (semi-confidentially) that it is an add-on that causes the issues (not a hardware problem after stress tests proved all good). I unloaded my community folder and all airport scenery addons, and now I’m doing the same flight over and over as I slowly add things back in. It’ll take me a few days, but I now have 2x flights successfully completed, and I’m on the third. Probably a good 10-15 more test flights, and each one is 3:45 real time. Thank you autopilot, cause it’s turned on at 400 feet after T/O and I walk away… shopping, out to dinner, you name it. haha!

I am having approximately the same issue for the last month, though my screen freezes 20 - 40 minutes into almost every flight while in flight. It happens no matter where I choose to fly, regardless of aircraft choice and I have only landed 3 out of 30+ flights. The screen freezes, but I still have sound and can tell from the sound that controller inputs are still working. The screen stays frozen, I cannot leave it with standard Alt + Tab or CTRL+ALT+DEL keyboard commands and have to reset the PC to escape the program. I have extensively tried all the fixes related here in the forums and the MSFS 2020 help pages as well whatever made sense from Youtube “expert” videos. I also have carefully monitored my hardware configurations and temps - running 90 fps avg, 70-75C GPU (RTX 3080), 70C avg CPU, and the SDK FPS overlay is always in the green.

I can go into an exhausting list of all the things I’ve tried to alleviate this issue as well as a hardware rundown if that helps anyone who can help me with this, but I’ll have to type it up. I can also furnish the error dialogs but they sure are extensive and big. I don’t use any mods, have nothing in my Community folder as yet and all goes well until mid-flight. I also have AIs pretty much turned off, random air and ground traffic turned off and have optimized my Nvidia drivers etc. as best possible, so it is perplexing and frustrating to say the least.

I can only suggest that you follow the same steps as I am: completely clean out your community folder and remove any add-ons thru Content Manager. Then slowly add them back in while doing test flights over and over and over. I am about halfway through this, and it looks like I may have identified the issue. It takes absolutely forever to do this, and it only really works if you have a particular flight that would freeze/crash/lockup on every single flight, so you can use this problem flight as the test (I do, so that helps a lot).

Load your sim in Developer Mode to see that when it freezes that you can un-pause it using the unpause in the dev mode menu.