Extension not loading in vault 2025

[tinuthomasGE9RJ]

Hello team,

 I tried to load my custom IExplorerExtension to vault 2025 using the SDK. But the extension is not loading. I Used .NET Framework 4.8.  Vcet.config file:
<configuration>
<connectivity.ExtensionSettings3>
<extension
interface="Autodesk.Connectivity.Explorer.Extensibility.IExplorerExtension, Autodesk.Connectivity.Explorer.Extensibility, Version=30.0.0.0, Culture=neutral, PublicKeyToken=215b0879a7566597"
type="MyNameSpace.MyClassName, MYAssemblyName">
</extension>
</connectivity.ExtensionSettings3>
</configuration>

given :

1. AssemblyCompany 
2. AssemblyProduct  
3. AssemblyDescription 
4. ExtensionId 
5. ApiVersion("18.0")

I Used IExplorerExtention, no response or not created any advanced toolbar/tools.

Then I tried SDK samples, That working fine. When I copy the same sample outside c drive it won't work. Could any one help me on this??

[Jaapflonk1]

I have this issue too. We upgraded to Vault 2025 and now our extensions don't work anymore.

Did you find a solution?

[marcelo.zatteraBGGNH]

Hi!

I think you need to migrate to .NET Core as explained in this topic.

Port .Net Framework-based project to .Net 

[Markus.Koechl]

Vault Client 2025 extensions must continue using the .NET Framework! Only 2025 CAD plug-ins must migrate to .NET Core. Event handlers are expected to handle CAD plug-in triggered events, and Vault Client triggered events must be compiled and installed twice: a .NET Framework version and a .NET Core version. See my blog article:  Autodesk Vault 2025 SDK - Breaking News - Under the Hood - All things PDM and PLM.

[mslosar]

Was this ever resolved? I'm having the same issue.  I started a new class library, set everything per the SDK help file and the HelloWorld example, but it simply does not load. There's no indication of why it isn't loading either. No errors, just does nothing.

[tinuthomasGE9RJ]

Please check and confirm the generated .dll and the .vcet file is unblocked. 

[balachandar_vVF4MG]

was this resolved ? if yes , how?

[FRFR1426 · Accepted solution]

Link to the blog article is broken. Here is the updated one: https://www.autodesk.com/blogs/design-and-manufacturing/2024/04/23/autodesk-vault-2025-sdk-breaking-...

[prudhvi_galiFSSED]

Thank you!

This solved the problem for me. I created the extension, so it was working perfectly fine. But when I shared it with my colleagues, it did not load in Vault since the files were blocked on their PCs. They had to manually unblock using the File Properties.

[esimers]

What?  
I don't understand this at all.

I'm just updating previous Vault Client plugins.  I used the internal Visual Studio 22 conversion to update to .net 8.  I get the files compiled but the extension never loads in the client.  Explain this like I'm 12 yrs old or something.  
Autodesk links for articles are all broken, half the documentation is not updated or confusing because it's so broken on what we are using, Core, Framework, 4.8 whatever.  I don't want old code anymore, I'm trying to modernize our plugins.  We need a real tutorial or walkthrough that's MODERN!! Please help us!

[Markus.Koechl]

I regret the bad experience you are making using our documentation. Blog articles are affected by significant changes and I hope that I can provide the links you need here. The first, clarifying what platform to use is this one: Autodesk Vault 2025 SDK - Breaking News - Design & Manufacturing.
To put it into a nutshell: if you intend to modernize your code you should know, that CAD plug-ins for Inventor, AutoCAD and Revit 2025 accept (and require) .NET Core based addins. Vault Client extension 2025 continue requiring .NET Framework based extensions. So, the full .NET Core unification is possible with Vault 2026 onwards, not with 2025.

[esimers]

Markus yes, I am working on updating everything to be compatible with 2026 Vault.
Unfortunately, the Vault extension I am working on was specifically designed for .Net 4.8.  I need to update it to .net 8.  I can get everything to compile, not errors.  But I cannot get it to load in Vault.  I looked at the 2026 sdk sample.  I was able to get it to load without issue.  So obviously I'm missing something somewhere in our custom one.  There's not a .addin file like Inventor for Vault but what exactly is the Minium requirement to get a plugin to load in Vault 2026?

[Markus.Koechl]

The minimum requirements to load an extension did not change. SDK documentation and sample for the *.vcet.config are valid: Getting Started -> How to customize Vault Explorer.
Did you mind updating the API version number to 19.0?

I personally stopped using the migration tool to update .NET 4.8 projects to .NET 8.0. Instead, I recommend creating a new .NET 8 project and copying code or module files into this project. I believe it is much faster than cleaning the migrated one.

If you continue having an issue loading a clean project, you could add the ExtensionLoadConfig.xml to the root ... Vault Client 2026\Extensions\ folder. SDK documentation, Knowledge Base -> Extension Loading Error Logging shares detailed instructions and an xml template.
I hope this helps.

[esimers]

Yeah, I think I will try copying everything into a brand new project.

Besides that this old one is in VB.net and I am just now understanding c#
beginning levels.

I will let you know what I find out.

[hans_martin_haga]

---

@Markus.Koechl wrote:

To put it into a nutshell: if you intend to modernize your code you should know, that CAD plug-ins for Inventor, AutoCAD and Revit 2025 accept (and require) .NET Core based addins. Vault Client extension 2025 continue requiring .NET Framework based extensions. So, the full .NET Core unification is possible with Vault 2026 onwards, not with 2025.

---

Is there any chance of Autodesk reconsidering this decision? We have an application using the IExplorerExtension and the customer is not ready for a 2026 upgrade. As it works in 2026, it should be possible for Autodesk to address this in a servicepack for 2025? Autodesk removing/breaking API functionality every other year cause a lot of headache.

[Markus.Koechl]

No, you cannot change a software's underlying development framework with a service pack or minor update. 

Starting with the 2026 product portfolio, you will see minor updates following the .NET Core pattern, similar to what we have seen in the past decades with .NET Framework.

I hope you understand this from a technical perspective.

[esimers]

so hey @Markus.Koechl   

I found a thing in the documentation help file on logging the loading of a Vault Extension!.

10/28/2025 8:09:41 AM ******************************************************************************
Autodesk.Connectivity.Extensibility.Framework Error: 1 : Autodesk.Connectivity.Extensibility.Framework.ExtensionException: No Company attribute specified for extension PMCAutodeskVaultCmds
   at Autodesk.Connectivity.Extensibility.Framework.ExtensionAssembly.CheckSettings()
   at Autodesk.Connectivity.Extensibility.Framework.ExtensionAssembly.Load()
ErrorCodeEnum: NoCompanyInformation

What does that error actually mean?  Do I not have a company name somewhere, and that is actually making it fail to load??  If so that's crazy... 

[FRFR1426]

You need to add the following attribute to your AssemblyInfo.cs file.

[assembly: AssemblyCompany("Your company name")]

If you are using a modern .csproj, you can use the following code:

<PropertyGroup>
  <Company>Your company name</Company>
</PropertyGroup>

This attribute is mandatory.

Please read the section "How to customize Vault Explorer" in the SDK help file.

[esimers]

hey so yeah after I did that, I was good, but the odd thing is in my proj file I has assembly information like <company> but it didn't pick them up?  The really odd thing is that when I first attempted to put them in the assembly file is VS22 warned me that I could not have that in two places at once.  I had to remove it from my proj file.  I also had to do the same with the <description> tag as well.  

Now that it's loading, I have bigger issues which would have to be another topic all together.  

Thanks! have a super awesome day!!

[FRFR1426]

When GenerateAssemblyInfo is true in your .csproj file, package-related project properties are transformed into assembly attributes.

https://learn.microsoft.com/en-us/dotnet/core/project-sdk/msbuild-props#generateassemblyinfo