Error: An assembly with the same name `Vuforia.UnityExtensions' has already been imported.

Questions & Answers
1

This project was working without issue until Unity crashed. Now on restart I can’t run it in the editor due to this issue. As you can see here all of the assemblies are coming from the install folder, I’ve deleted my Library and Temp folders and in fact completely re-installed Unity to no avail.

error CS1704: An assembly with the same name `Vuforia.UnityExtensions' has already been imported. Consider removing one of the references or sign the assembly
/Applications/Unity/Hub/Editor/2017.3.1f1/PlaybackEngines/VuforiaSupport/Managed/Runtime/Vuforia.UnityExtensions.dll (Location of the symbol related to previous error)
/Applications/Unity/Hub/Editor/2017.3.1f1/PlaybackEngines/VuforiaSupport/Managed/Android/Vuforia.UnityExtensions.dll (Location of the symbol related to previous error)
error CS1704: An assembly with the same name `Vuforia.UnityExtensions' has already been imported. Consider removing one of the references or sign the assembly
/Applications/Unity/Hub/Editor/2017.3.1f1/PlaybackEngines/VuforiaSupport/Managed/Runtime/Vuforia.UnityExtensions.dll (Location of the symbol related to previous error)
/Applications/Unity/Hub/Editor/2017.3.1f1/PlaybackEngines/VuforiaSupport/Managed/iOS/Vuforia.UnityExtensions.dll (Location of the symbol related to previous error)
error CS1704: An assembly with the same name `Vuforia.UnityExtensions' has already been imported. Consider removing one of the references or sign the assembly
/Applications/Unity/Hub/Editor/2017.3.1f1/PlaybackEngines/VuforiaSupport/Managed/Runtime/Vuforia.UnityExtensions.dll (Location of the symbol related to previous error)
/Applications/Unity/Hub/Editor/2017.3.1f1/PlaybackEngines/VuforiaSupport/Managed/WindowsStoreApps/Vuforia.UnityExtensions.dll (Location of the symbol related to previous error)

Compilation failed: 3 error(s), 0 warnings
2

I also see a series of errors like this on start:

Assertion failed: Extension /Applications/Unity/Hub/Editor/2017.3.1f1/PlaybackEngines/VuforiaSupport/Managed/iOS/Vuforia.UnityExtensions.dll was not registered, that means it relies on default UnityExtensions settings, please register extension and apply necessary settings for it in the callback.

3

Anyone find an answer to this issue? I’m having the same issue on the updated version of Unity.,Does anyone know how to fix this issue. I’m looking everywhere and I can’t find a thing. I have 3 laptops and I used an old version with no issues. Updated and now that one has the same issue. How can I fix this.

4

I managed to solve the issue!
The problem appeared because you installed Vuforia unity extension and also imported Vuforia extension that you downloaded from the net.
You need to get ride of one so you either reinstall unity and manually ad extension or just delete what u manually added . If you chose second option you will probably need to add Vuforia components again (gameobject → Vuforia ) .
I used first method and it worked. Before that my unity project just crushed when i tried to open it.
I hope that this helped!