Assembly with same name is already loaded
- Chris Price
Problem
You receive an error message stating “Xrev Transmit add-in failed to start” in Revit 2025
An error occurred during startup of the Xrev Transmit add-in and the add-in could not be loaded. System.IO.FileLoadException: Assembly with same name is already loaded.
Due to the switch from .NET Framework 4.8 to .NET Core 8.0 in Revit 2025, these types of conflicts are far more likely to occur. Autodesk are working on a potential solution in the next version of Revit, however this will likely always be an issue in Revit 2025.
Solution
This is caused by another add-in using similar 3rd party components as Transmit, but a different version creating a conflict. We are aware of several add-ins currently that cause conflicts.
Revizto 5
Revizto utilises some of the same 3rd party assemblies that Transmit uses, however Revizto are using .NET 4.8 framework versions instead of the required .NET 8 versions as required in Revit 2025 (The Revitzto add-does not play nice with others because of this). Xrev reported this to their support back in September 2024. Revizto advised some time ago that they have resolved this in their upcoming 5.16 release which has not been released. For now, please temporarily disable the Revizto plugin by renaming the .addin file extension (.addinbak). This will allow ours to run after restarting Revit as the Revizto add-in will not load while this is the case. Then rename the Revizto again when you need to use it.
The 2025 add-in files are located in these 2 locations:
C:\ProgramData\Autodesk\Revit\Addins\2025
OR%appdata%\Autodesk\Revit\Addins\2025
(Copy this path into your address bar)
StructSoft MWF Pro Metal
MWF Pro Metal is loading an assembly named "Microsoft.Bcl.AsyncInterfaces" which we also load for Transmit. This is a relatively common dependency for .NET applications, however, the problem is that they're using an older version (assembly version 1.0.0.0, file version 4.700.20.21406) and we're using a newer version (assembly version 6.0.0.0, file version 6.0.21.52210). Unfortunately their add-in cannot be disabled using the conventional way and must be uninstalled. They've advised this issue is very difficult for them to resolve.
Allegion Overtur
As above, you can temporarily rename their .addin file when you need to use Transmit. One of our customers has advised Allegion of the conflict and we are waiting to hear back.