Labview crash, 0xc0000005, mgcore_SH_26_1.dll

[anxious_labviewer]

I've been using Labview quite smoothly for the past 3 years but the recent week is a big disaster...

So my codes have been smooth and normal until Apr 6th, then when I tried to run it again on Apr 8th, it started to have problems. (strangely, nothing like a windows update has happened)

The program can run for a short bit of time, but then would crash and flash close with no apparent error message.

In task manager nothing was crazy/off. Just ~30% of CPU and memory were being used.

This computer is on windows10, and the labview I'm using is on 2023 Q1.

When I checked the event viewer, it seems that the crashing reason is:

Exception code:0xc0000005

And the file related to the crash is: C:\Program Files\National Instruments\LabVIEW 2025\resource\mgcore_SH_25_1.dll

I've tried the following things but none of them have worked:

1. Use "repair" in the NI package manager

2. Uninstall, and then reinstall.

3. I found the "uninstall" doesn't seem complete (I was first trying using NI package manager to uninstall other stuff, then in "add/remove program" to uninstall NI manager), and many folder were left on the computer, so I manually enter the safe mode to delete everything related to "National Instruments" in the following paths:

C:\Program Files

C:\Program Files (x86)

C:\ProgramData

C:\Users\<my user name>\Document

C:\Users\<my user name>\AppData\Local

C:\Users\<my user name>\AppData\Roaming

C:\Users\Public\Document

4. As for reinstall, I've tried the latest version 2025 Q1, or 2024 Q3, or 2023 Q1.

5. Some repeating combinations of "repair" "uninstall" "reinstall"

6. Besides this lab computer that I was using, I also tried my personal laptop, which is on windows11 and clean of any install. Surprisingly, the same crash issue occurs.

While I have not solved the crashing problem, some new problems arose as well: as of now, it seems that I couldn't normally download labview via the link from ni.com.

The error message for this:

"A error occurred while creating a process to run command: C:\Program Files (x86)\National Instruments\Shared\RegistrationWizard\Bin\RegistrationWizard.exe -rebootFirst .... "

So I found that in this path (C:\Program Files (x86)\National Instruments\Shared\), there is no folder named "RegistrationWizard".

Additionally, sometime there is also this error message:

"...\nimdnsNSP.dll" is blocked from loading into the local security authority

[Kyle97330]

The last message about the local security authority is covered extensively in this thread:

https://forums.ni.com/t5/LabVIEW/Local-Security-Authority-LabView-2024-Q3/td-p/4394721

Short version is that it's not a real problem, just a false positive, and it's fixed in the NI System Configuration 2025Q2 release.

"mgcore" appears to be a memory management DLL.  There's not a lot about it out there but there is this:

https://lavag.org/topic/17810-memory-deallocation-bug/page/2/

Since it's a memory management problem, it could indicate faulty RAM.  Perhaps try running the "Windows Memory Diagnostic" tool that will scan all the RAM on your PC for problems.

I'm not sure of the best way to reinstall, though.

[anxious_labviewer · Accepted solution]

Thanks for pointing to the two threads! very helpful 😊

As a quick check, I followed what is discussed in the second link:

1. Cut mgcore_SH_25_0.dll, and save it elsewhere

2. renamed mgcore_25_0.dll to be mgcore_SH_25_0.dll

This is definitely improving - previously I can only run ~6 trials, now I'm at the 14th trial and the code has not crashed yet.

Will double check tmr and if it's really working safely I will call this as resolved!