FlightStream 2025 (Windows) crashing on all unsteady simulations

BuggsBunny

Hello,

I have an issue where FlightStream 2025 crashes every time I run an unsteady simulation. I did not have this issue with the 2023 version. I have a Windows machine with 64gb of RAM and 32 parallel threads. I have tried running the same simulation on a Linux machine and it works fine. I have tried uninstalling and re-installing, but it has not fixed the issue. I have also tried running the 2024 version and it crashes as well.

Is there a way I can fix this issue?

Thanks

Edit: It only crashes if I go beyond 10 parallel threads. I monitored my CPU and it's not being used more than 30% (occasionally jumps to 50%).

I performed a couple of stress tests on the machine at full capacity, and they work fine..

CoryG

This is very odd. Can you share your simulation file?

denriquez

based on the image, I also wonder if the wake is getting to 'heavy' for the machine at some point. typically we recommend truncating the wake after 36-48 time steps. This can be toggled in the Options>Advanced>Settings>Wake Termination Time Steps

BuggsBunny

@CoryG like I said, it happens in all unsteady simulations. But if it helps, I have attached the files below.

based on the image, I also wonder if the wake is getting to 'heavy' for the machine at some point.

@denriquez I have tried truncating and it still crashes. Like I mentioned in my edit, the resource monitor indicates that no more than 30% of the resource is being used.

Also, it is very strange that it does not crash if I allocate less than 10 cores for the simulation.

unsteady_Crash.zip

CoryG

Thanks for sharing the files.

Unfortunately, I'm unable to reproduce the crash with the provided files on either version 2025 or my latest dev version. Is there a specific point/timestep in the simulation at which it is crashing?

BuggsBunny

@CoryG No, it is random. Can you try simulating by allocating all the cores available in your system?

I tried to capture a few crash reports, almost all of them point towards "ucrtbase.dll" and a couple of them point towards "libiomp5md.dll". This might be of help to you:

Faulting application name: FlightStream.exe, version: 0.0.0.0, time stamp: 0x6785961f
Faulting module name: ucrtbase.dll, version: 10.0.26100.3037, time stamp: 0x8481217d
Exception code: 0xc0000005
Fault offset: 0x0000000000012b3a
Faulting process id: 0x4264
Faulting application start time: 0x1DB8F1E1BCE065D
Faulting application path: C:\Program Files\Altair\2025\flightstream\FlightStream.exe
Faulting module path: C:\WINDOWS\System32\ucrtbase.dll
Report Id: 6c23a318-1714-4b90-8053-966418ee53e8
Faulting package full name:
Faulting package-relative application ID:

I can confirm, I'm running the latest Microsoft Visual C++ Redistributable Packages

I tried a system scan to check for any issues and there seems to be no issues.

Beginning system scan. This process will take some time.

Beginning verification phase of system scan.
Verification 100% complete.

Windows Resource Protection did not find any integrity violations.

I managed to create a dump file and recreate the crash for you to analyze. When I analysed this on WinDbg I got:

0:024> .ecxrrax=0000000000000000 rbx=0000020df318f0b0 rcx=0000020df2bbc4f0rdx=0000000000000002 rsi=00000060b8a1e400 rdi=0000000000000000rip=00007ffdb0b32b3a rsp=00000060b8a1e260 rbp=0000000000000000 r8=0000000000000012 r9=0000020df28c98a0 r10=00000060b8a1e388r11=00000060b8a1e390 r12=00007ff77b8b0a38 r13=00007ff77b8af980r14=00007ff77b8af858 r15=0000000000000022iopl=0 nv up ei pl nz na po nccs=0033 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010204ucrtbase!_errno+0x7a:00007ffd`b0b32b3a 4869f8c8030000 imul rdi,rax,3C8h0:024> !analyze -v******************************************************************************** ** Exception Analysis ** ********************************************************************************KEY_VALUES_STRING: 1 Key : AV.Type Value: Write Key : Analysis.CPU.mSec Value: 828 Key : Analysis.Elapsed.mSec Value: 40083 Key : Analysis.IO.Other.Mb Value: 4 Key : Analysis.IO.Read.Mb Value: 1 Key : Analysis.IO.Write.Mb Value: 48 Key : Analysis.Init.CPU.mSec Value: 281 Key : Analysis.Init.Elapsed.mSec Value: 36952 Key : Analysis.Memory.CommitPeak.Mb Value: 91 Key : Analysis.Version.DbgEng Value: 10.0.27793.1000 Key : Analysis.Version.Description Value: 10.2410.02.02 amd64fre Key : Analysis.Version.Ext Value: 1.2410.2.2 Key : Failure.Bucket Value: NULL_CLASS_PTR_WRITE_INVALID_POINTER_WRITE_c0000005_ucrtbase.dll!_errno Key : Failure.Exception.Code Value: 0xffffffffc0000005 Key : Failure.Exception.IP.Address Value: 0x7ffdb0b32b3a Key : Failure.Exception.IP.Module Value: ucrtbase Key : Failure.Exception.IP.Offset Value: 0x12b3a Key : Failure.Hash Value: {b6eb34c4-cecd-afb1-b76f-1bbe6582076b} Key : ProblemClass.Collapse.After.BUCKET_ID Value: NULL_CLASS_PTR_WRITE_INVALID_POINTER_WRITE Key : ProblemClass.Collapse.After.DEFAULT_BUCKET_ID Value: NULL_CLASS_PTR_WRITE_INVALID_POINTER_WRITE Key : ProblemClass.Collapse.After.PRIMARY_PROBLEM_CLASS Value: NULL_CLASS_PTR_WRITE Key : ProblemClass.Collapse.Before.BUCKET_ID Value: NULL_CLASS_PTR_WRITE_INVALID_POINTER_WRITE Key : ProblemClass.Collapse.Before.DEFAULT_BUCKET_ID Value: NULL_CLASS_PTR_WRITE_INVALID_POINTER_WRITE Key : ProblemClass.Collapse.Before.PRIMARY_PROBLEM_CLASS Value: NULL_CLASS_PTR_WRITE Key : Timeline.OS.Boot.DeltaSec Value: 602306 Key : Timeline.Process.Start.DeltaSec Value: 181 Key : WER.OS.Branch Value: ge_release Key : WER.OS.Version Value: 10.0.26100.1FILE_IN_CAB: FlightStream.exe.2336.dmpNTGLOBALFLAG: 0APPLICATION_VERIFIER_FLAGS: 0CONTEXT: (.ecxr)rax=0000000000000000 rbx=0000020df318f0b0 rcx=0000020df2bbc4f0rdx=0000000000000002 rsi=00000060b8a1e400 rdi=0000000000000000rip=00007ffdb0b32b3a rsp=00000060b8a1e260 rbp=0000000000000000 r8=0000000000000012 r9=0000020df28c98a0 r10=00000060b8a1e388r11=00000060b8a1e390 r12=00007ff77b8b0a38 r13=00007ff77b8af980r14=00007ff77b8af858 r15=0000000000000022iopl=0 nv up ei pl nz na po nccs=0033 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010204ucrtbase!_errno+0x7a:00007ffd`b0b32b3a 4869f8c8030000 imul rdi,rax,3C8hResetting default scopeEXCEPTION_RECORD: (.exr -1)ExceptionAddress: 00007ffdb0b32b3a (ucrtbase!_errno+0x000000000000007a) ExceptionCode: c0000005 (Access violation) ExceptionFlags: 00000000NumberParameters: 2 Parameter[0]: 0000000000000001 Parameter[1]: 0000000000000003Attempt to write to address 0000000000000003PROCESS_NAME: FlightStream.exeWRITE_ADDRESS: 0000000000000003 ERROR_CODE: (NTSTATUS) 0xc0000005 - The instruction at 0x%p referenced memory at 0x%p. The memory could not be %s.EXCEPTION_CODE_STR: c0000005EXCEPTION_PARAMETER1: 0000000000000001EXCEPTION_PARAMETER2: 0000000000000003STACK_TEXT: 00000060`b8a1e260 00007ff7`7b7ad99f : 00000060`b8a1e408 00000060`b8a1e400 bfd2aff1`b01d70df 00000000`00000000 : ucrtbase!_errno+0x7a00000060`b8a1e2a0 00000060`b8a1e408 : 00000060`b8a1e400 bfd2aff1`b01d70df 00000000`00000000 3fd4d143`c2846c34 : FlightStream+0x5ed99f00000060`b8a1e2a8 00000060`b8a1e400 : bfd2aff1`b01d70df 00000000`00000000 3fd4d143`c2846c34 00000000`00000000 : 0x00000060`b8a1e40800000060`b8a1e2b0 bfd2aff1`b01d70df : 00000000`00000000 3fd4d143`c2846c34 00000000`00000000 3fb2e669`ed6dab12 : 0x00000060`b8a1e40000000060`b8a1e2b8 00000000`00000000 : 3fd4d143`c2846c34 00000000`00000000 3fb2e669`ed6dab12 00000000`00000000 : 0xbfd2aff1`b01d70dfSYMBOL_NAME: ucrtbase!_errno+7aMODULE_NAME: ucrtbaseIMAGE_NAME: ucrtbase.dllSTACK_COMMAND: ~24s; .ecxr ; kbFAILURE_BUCKET_ID: NULL_CLASS_PTR_WRITE_INVALID_POINTER_WRITE_c0000005_ucrtbase.dll!_errnoOS_VERSION: 10.0.26100.1BUILDLAB_STR: ge_releaseOSPLATFORM_TYPE: x64OSNAME: Windows 10IMAGE_VERSION: 10.0.26100.3037FAILURE_ID_HASH: {b6eb34c4-cecd-afb1-b76f-1bbe6582076b}Followup: MachineOwner---------

Unfortunately, I'm unable to attach the dump file as it's over 100mb. You can download the dump file from here. Let me know if the OneDrive link does not work or if you do not have permission to access it.

Hopefully this must be enough to recreate or solve the bug.

CoryG

I've run with varying numbers of threads up to my maximum of 28. I will try to look through the dump file. Until we're potentially able to solve this, the workaround would be to run on no more than 10 threads. With how FlightStream is parallelized, I don't think you'll be sacrificing too much performance anyway.