Add-in crashes on client's machine

[Kevin_Andras]

Hi - I have been developing an add-in for Pro 3.3, using the latest SDK and Visual Studio 2022.  I have several clients using it successfully.  One client is able to install the add-in, but any time a button on the toolbar is clicked, Arc closes and pops up the error reporting message. 

To rule out any problem with my code, I built another basic add-in with no code other than to create a button on a toolbar to load a ProWindow.  On the client's machine, as soon as that is clicked, Arc crashes. The client machine has ArcGIS Pro 3.3 installed locally (not a virtualization), and has .NET version 8.0.112.    The add-in files are installed to C:\Users\[USERNAME]\AppData\Local\ESRI\ArcGISPro\AssemblyCache\{d6086f3c-6207-4a54-8c73-2c965f1a45c2}

What else should we look for to try to get this working?   Thanks for any help. I am at a loss.

[Kevin_Andras]

I was able to analyze the crash report from a machine running ArcGIS Pro 3.3.  It indicated this:

CLR exception type: System.IO.FileNotFoundException
    "Could not load file or assembly 'ArcGIS.Desktop.Mapping, Version=13.4.0.0, Culture=neutral, PublicKeyToken=8fc3cc631e44ad86'. The system cannot find the file specified."

Then, I rebuilt the add-in, and set all of the ArcGIS assemblies to Copy Local = Yes. After that, it still crashed, and the error report now says this:

CLR exception type: System.Windows.Markup.XamlParseException
    "Could not load file or assembly 'ArcGIS.Desktop.Extensions, Culture=neutral, PublicKeyToken=8fc3cc631e44ad86'. The system cannot find the file specified."

The client computer has the ArcGIS.Desktop.Extensions.dll file in its normal installation location.  

[Kevin_Andras]

Seems that everything works fine on 3.4 installations, but 3.3 installations cause these errors.  It's specifically built for 3.3, though:

<AddInInfo id="{7b259974-f6fe-4a27-8a7d-c1402f40f8df}" version="1.0" desktopVersion="3.3" product="ArcGISPro">

Before I updated my SDK to the latest version, anything I built worked fine on a 3.3 installation.

[Kevin_Andras · Accepted solution]

After a lot of searching, and scratching my head, I found a random blog post about making sure that .csproj files refer to Nuget packages instead of .DLLs:

https://mykeels.medium.com/stop-using-the-old-csproj-sdk-format-ae78e0c782bd

That led me to find this: 

https://www.nuget.org/packages/Esri.ArcGISPro.Extensions30

And after I installed Esri.ArcGISPro.Extensions30, version 3.3.3.52636, everything works on a 3.3 installation.