Issue with RevitAddInUtility for Revit 2025-2026 and customized installer

[m.vallee]

Hi,

Here I am again with a very old problem coming back (please see https://forums.autodesk.com/t5/revit-api-forum/issue-with-revitaddinutility-for-revit-2019-and-custo...

I am migrating my Revit plugins to versions 2025 and 2026 of the API, and I am struggling with the update of the deployment part in Visual Studio.

My setup project uses another project called "RegisterRevitAddin" to write/delete needed manifest files at the required locations for each installed Revit version, using the RevitAddInUtility DLL (please see this link). So as I've been doing for the last 8 years without any problem, I've changed the reference to RevitAddInUtility to use the new 2026 version, and made a few changes in my custom actions' code to support Revit 2025 & 2026 manifest registrations. Then I've successfully recompiled both projects and tried to execute the installer on my machine. I have the following error : "Error 1001. Unable to load file or assembly 'RevitAddInUtility, Version=26.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependancies. The specified file could not be found."

Again the only difference I see between 2024 and 2025-2026 versions of the DLL is the "processorArchitecture" tag when adding the reference in the C# project : for 2024 it is "MSIL", for 2025 and 2026 it is "AMD64".

Could you please provide us the "MSIL" compil version of the 2026 RevitAddInUtility DLL ?

Thanks for your help.

[ricaun]

It's kind of hard to know what the problem is without a proper project example with "RegisterRevitAddin" implementation. If you shared some sample project in the GitHub should be helpful.

I actually creates the manifest file and the bundle folder when creating my installation for my Revit plugins. I'm not using the RevitAddInUtility.dll and PackageContentsParser.dll.

I use this package Autodesk.PackageBuilder and I created that library to basically make the same thing, create the manifest file for Revit and the bundle (PackageContents.xml) for my Revit applications.

Actually I recent update the package to support manifest for Revit and Inventor, and bundle for AutoCAD, Revit, 3ds Max, Inventor, Maya, and Navisworks.

The project is open source.

• https://github.com/ricaun-io/Autodesk.PackageBuilder

And you could create the RevitAddin.addin like this:

var builder = BuilderUtils.Build<RevitAddInsBuilder>(builder =>
{
    builder.AddIn.CreateEntry("Application")
        .Name("RevitAddin")
        .AddInId("11111111-2222-3333-4444-555555555555")
        .Assembly("RevitAddin.dll")
        .FullClassName("RevitAddin.App")
        .VendorId("RevitAddin")
        .VendorDescription("RevitAddin");
});
builder.Build("RevitAddin.addin");

I hope that helps somehow.

See yaa!

[m.vallee]

Thanks for your help but this is not what I need : I don't want to change my way to create manifest files during setup...

I just want to get the MSIL version of the 2026 RevitAddinUtility DLL instead of the AMD64 one...

[ricaun]

---

@m.vallee wrote:

I just want to get the MSIL version of the 2026 RevitAddinUtility DLL instead of the AMD64 one...

---

I can't help with that. I know version 2026.0 have a bug in the RevitAddinUtility.dll related with the Context configuration. Was fixed in the 2026.1 Revit release.

Usually is easier and faster to create/use a package instead of waiting Autodesk to do what you want.