ntdll.dll error when opening 2nd Excel instance manually

[bpier...@gmail.com]

I had been on Excel DNA 1.8, and a customer reported that opening a 2nd Excel process (holding ALT key down when opening) was causing the new instance to freeze, and then on subsequent loads it would warn about a problem with the add-in. I recently upgraded to the latest 1.9 beta, and interestingly I now see the same behavior. Possibly it was there before, but point being it's still there. I'm on a very recent x64 version of Excel and Windows 11. Using .NET Framework for add-in, not .NET core. I confirmed that if I unload the add-in, then I can open multiple instances of Excel this way.

Interestingly, this only occurs when starting a 2nd process manually. My add-in has a feature for launching new Excel instances, and that can launch a 2nd Excel instance without issue. It does that using this:

  var psi = new ProcessStartInfo(<path to Excel.exe>, "/x") { UseShellExecute = true };

 Process.Start(psi);

I'll spend more time playing with this, but posting in case anybody is aware of this one.

Here is the error from the Windows event viewer:

Faulting application name: EXCEL.EXE, version: 16.0.18827.20140, time stamp: 0x683dce73
Faulting module name: ntdll.dll, version: 10.0.26100.4202, time stamp: 0x9194561f
Exception code: 0xc00000fd
Fault offset: 0x00000000001661d7
Faulting process id: 0x6FC0
Faulting application start time: 0x1DBDFA2A1A37B12
Faulting application path: C:\Program Files\Microsoft Office\root\Office16\EXCEL.EXE
Faulting module path: C:\WINDOWS\SYSTEM32\ntdll.dll
Report Id: d01433c9-0300-477f-8702-7de408e6378c
Faulting package full name:
Faulting package-relative application ID: 

...and here's the Info message written 2 seconds later:

Fault bucket 1815234883633292197, type 5
Event Name: OFFICE_MODULE_VERSION_MISMATCH
Response: Not available
Cab Id: 0

Problem signature:
P1: EXCEL.EXE
P2: 16.0.18827.20150
P3:
P4:
P5:
P6:
P7:
P8:
P9:
P10:

[bpier...@gmail.com]

I just tried creating an Excel shortcut on the desktop with the "/x" switch after the path to Excel.exe, and that also works. So it's just trying to use the ALT key to launch a 2nd instance that fails. The new instance freezes on the splash screen for a minute-ish then crashes, and after that it will warn about issues with the add-in and and ask about disabling it. Very strange.

[Govert van Drimmelen]

I’ve updated to the latest current channel version of Excel

  Microsoft® Excel® for Microsoft 365 MSO (Version 2505 Build 16.0.18827.20102) 64-bit

It looks like you have a slightly newer build, but not much.

 

I don’t see any problem with a simple add-in (built with v1.9.0-beta2) that does include a ribbon (so gets the Application object and loads the extra COM add-in during startup).

I have the add-in installed, so it loads automatically when Excel starts.

Multiple Excel processes start without problem.

 

What is the simplest add-in that reproduces the issue for you?

Does your add-in do anything exciting in the AutoOpen or the ribbon class loading?

I presume when starting from the Alt+taskbar click that you see the little “Do you want to start a new instance of Excel?” dialog, and you don’t see this when starting with “/x” from the shortcut?

 

-Govert

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[bpier...@gmail.com]

Seems to be some incompatibility with ExcelDna and something with Excel that updated on my machine, as this is something that just started recently. The add-in I built is running on hundreds of machines, and I've only had 1 report of the same thing ...though I recall now that it did happen a few months ago on a Windows Surface laptop I'm decommissioning, but I didn't think much about it at the time.

I created a brand new C# Library project (.NET Framework) in Visual Studio 2022, added only the ExcelDna.AddIn project (1.9.0-beta2) as a dependency, which also added ExcelDna.Integration, then built the project and tried to use the add-in. On opening the first instance I get ExcelDna diagnostic display with this expected error:

Initialization [Error] No objects loaded from ExcelInstancesTest, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null

...and then when holding the ALT key down and clicking "Yes" to launch a fresh instance, it just freezes on the splash screen for 1 minute (1 minute, and 2 seconds when timed) before crashing (splash screen just disappears, and also gone in Task Manager). Then I get the "Excel is running into problems ...do you want to disable?" dialog when next opening Excel. The shortcut to launch a new instance continues to work without issue, with each new instance opening quickly and showing that error in the Diagnostic Display. I did confirm that after removing the add-in, I can open multiple Excel instances using the ALT key without any problem.

The same error/info was in the Windows event log (pasted below). FYI that my ntdll.dll in C:\Windows\System32\ has file version 10.0.26100.4202 - it's size is 2,513,744 bytes (size on disk is 2,514,944) and it was signed May 23, 2025. Let me know if there's any other info I can provide. Seems like Microsoft may be pushing some new and problematic dll, maybe in a staged rollout which accounts for the low incident rate. I'm not super hopeful there's a lot you can do on this one.

From Windows event log:

Faulting application name: EXCEL.EXE, version: 16.0.18827.20150, time stamp: 0x68424989
Faulting module name: EXCEL.EXE, version: 16.0.18827.20150, time stamp: 0x68424989
Exception code: 0xc0000005
Fault offset: 0x00000000003f108d
Faulting process id: 0x5934
Faulting application start time: 0x1DBDFE8F7402D77

Faulting application path: C:\Program Files\Microsoft Office\root\Office16\EXCEL.EXE

Faulting module path: C:\Program Files\Microsoft Office\root\Office16\EXCEL.EXE
Report Id: 49b8c345-f0ed-457d-92b8-bf877f5ccb11

Faulting package full name:
Faulting package-relative application ID:

Fault bucket 1815234883633292197, type 5
Event Name: OFFICE_MODULE_VERSION_MISMATCH
Response: Not available
Cab Id: 0

Problem signature:
P1: EXCEL.EXE
P2: 16.0.18827.20150
P3:
P4:
P5:
P6:
P7:
P8:
P9:
P10:

Attached files:
\\?\C:\Users\bpier\AppData\Local\Temp\{495F05B3-748C-4044-933D-DF9BCF5C4429} - OProcSessId.dat
\\?\C:\ProgramData\Microsoft\Windows\WER\Temp\WER.1bbcac39-ee01-4ca7-8415-f9e5a2c2aa69.tmp.WERInternalMetadata.xml
\\?\C:\ProgramData\Microsoft\Windows\WER\Temp\WER.b145801a-c863-4a04-877e-ed4625f6862c.tmp.csv
\\?\C:\ProgramData\Microsoft\Windows\WER\Temp\WER.4b05de66-f9cf-4c61-bccb-d65df1b64a60.tmp.txt
\\?\C:\ProgramData\Microsoft\Windows\WER\Temp\WER.f75908f1-cd4e-4ba3-a04a-8bd09eb1d35b.tmp.xml

These files may be available here:
\\?\C:\ProgramData\Microsoft\Windows\WER\ReportArchive\AppCrash_EXCEL.EXE_efbedee5758e9a6ef1d41ec064e1913d73b86513_00000000_b4597616-fcce-4f9d-b0cc-02dc8c212328

Analysis symbol:
Rechecking for solution: 0
Report Id: 49b8c345-f0ed-457d-92b8-bf877f5ccb11
Report Status: 268435456
Hashed bucket: 6d7b17d84a5ec5364931028256dc23a5
Cab Guid: 0

[bpier...@gmail.com]

...I had selected .NET 4.8

[bpier...@gmail.com]

...and just for good measure, I just tried various suggestions from ChatGPT around setting the Isolation to "SeparateAppDomain" (also tried just "AppDomain") and ShadowCopy to false in the .dna file. No luck.

[bpier...@gmail.com]

Sorry for the spam, but one last update: I also tried with ExcelDna 1.8, 1.7 and 1.6 -- somewhat as expected given the nature of it, it was the same issue each time.

[Govert van Drimmelen]

Your error is an Access Violation (code 0xc0000005) in the Excel process. The appearance of “ntdll.dll” is just how the error is surfaced, and this Windows library is not likely to be involved.

 

I don’t know whether “OFFICE_MODULE_VERSION_MISMATCH” is a clue – I do see a few Google hits though nothing specific. It might be a diagnostic that Office runs after a crash, or something more indicative of the issue. Here’s an unrelated example discussion where it appeared recently Addin crashing on Current Channel Preview - Version 2505 Build 16.0.18827.20008 · Issue #5702 · OfficeDev/office-js.

 

From what you report, it seems an Office update might have broken this. Certainly you should report it with the Send a Frown button if you can.

 

Is the pattern of launching with the Alt-key detection for a new instance something your users are likely to do often? If not, it’s hard to tell how prevalent the issue is. I’ve certainly not heard of this behaviour before. In recent versions, when an Excel-DNA project is started in the VS debugger, a new process is started with the “/x” argument. But it sounds like this is not the error case you see.

 

I would suggest you go through the various Office repair options to see it that might help. Otherwise you can try older Office versions by either changing the update channel (Change the Microsoft 365 Apps update channel for devices in your organization - Microsoft 365 Apps | Microsoft Learn) or by reverting to a specific earlier version (How to revert to an earlier version of Office - Microsoft Support).

 

I suspect it’s something that goes wrong with a particular Office update sequence, or a version you have with some features flags enabled from Microsoft’s side.

 

Regards,

To view this discussion visit https://groups.google.com/d/msgid/exceldna/37665bae-bb9f-486d-9167-3d65b4b862dbn%40googlegroups.com.

[bpier...@gmail.com]

Thanks Govert -- I'll take those steps, as I agree it is an Excel issue. The Alt-key thing is done by several users, only because the process isolation is so important in trading organizations where spreadsheets tend to have lots of heavy logic and also lots of real-time data coming in ...but most of our users use our feature to launch new instances, which uses the /x switch and thankfully still works fine.

[Brian Pierce]

That was quick! Correct on seeing the “Do you want to start…” when using ALT but not with shortcut.

Trying to get to the simplest add-in that creates the problem… and reviewing my logic around open… is what I’ll be doing to try and isolate it. Will send what I find as I have more info.

Brian

On Jun 17, 2025, at 2:50 PM, Govert van Drimmelen <govert.va...@gmail.com> wrote:



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