Visio add-in crashes, Faulting module name: ntdll.dll

I have created Visio (VSTO) Com Add-in. After one of my users installed Visio 2016, Visio with the following error: "Visio is running into problems with the '[add in name]' add-in. If this keeps happening, disable this add-in and check the available updates. Do you want to disable it now?"

I not sure it's got to do with Visio 2016 only, but we've tried reinstall both 32/64 bit (on Windows 10 64 bit operating system)

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• Here's what I've seen in the "Event Viewer"

**: Faulting application name: VISIO.EXE, version: 16.0.11328.20368, time stamp: 0x5d173494 Faulting module name: ntdll.dll, version: 10.0.17763.1158, time stamp: 0x67e7a2b6 Exception code: 0xc0000374 Fault offset: 0x000e0e03 Faulting process id: 0x2c58 Faulting application start time: 0x01d637f389d9c14d Faulting application path: C:\Program Files (x86)\Microsoft Office\Root\Office16\VISIO.EXE Faulting module path: C:\WINDOWS\SYSTEM32\ntdll.dll Report Id: 3d86d759-b344-4d14-9487-1078fb895664 Faulting package full name: Faulting package-relative application ID:

I've done deep debugging and the location is random, but I have noticed that in many cases the crash is at "save" location: this.Application.ActiveDocument.Save();

I've done lots of web research and so far didn't find meaningful information.

Can anyone help on this?