We’re using Unity 2018.4.1f1 and trying to update the Facebook SDK to v7.17.0 but we’re getting the following error:
PrecompiledAssemblyException: Multiple precompiled assemblies with the same name Facebook.Unity.Android.dll included for the current platform. Only one assembly with the same name is allowed per platform. Assembly path: {0}
UnityEditor.Scripting.ScriptCompilation.EditorBuildRules.CreateTargetAssemblies (System.Collections.Generic.IEnumerable1[T] customScriptAssemblies, System.Collections.Generic.IEnumerable1[T] precompiledAssemblies) (at C:/buildslave/unity/build/Editor/Mono/Scripting/ScriptCompilation/EditorBuildRules.cs:249)
UnityEditor.Scripting.ScriptCompilation.EditorCompilation.UpdateCustomTargetAssemblies () (at C:/buildslave/unity/build/Editor/Mono/Scripting/ScriptCompilation/EditorCompilation.cs:625)
UnityEditor.Scripting.ScriptCompilation.EditorCompilation.SetAllCustomScriptAssemblyJsons (System.String[ ] paths) (at C:/buildslave/unity/build/Editor/Mono/Scripting/ScriptCompilation/EditorCompilation.cs:735)
UnityEditor.Scripting.ScriptCompilation.EditorCompilationInterface.SetAllCustomScriptAssemblyJsons (System.String[ ] allAssemblyJsons) (at C:/buildslave/unity/build/Editor/Mono/Scripting/ScriptCompilation/EditorCompilationInterface.cs:217)
We have tried the following:
- Deleting the duplicated Facebook.Unity.Android.dll and Facebook.Unity.iOS.dll. That solved our problem for Android but created more errors of Facebook library missing for iOS, so we reverted back.
- Disabling all services before updating
- Deleting the Library folder
The duplicated dll seem to be from the “facebook-unity-sdk-7.17.0.unitypackage”.
Is anyone else having this issue?
Any way to fix this ?
Thanks
I’m having the same problem. I’m pretty sure I already had the same problem with FacebookSDK. I just can’t remember how I solved it. I’ll let you know if I find a way to fix it.
Same situation for me, I had the same issue before and I solved it by doing what I’ve described above, but this time it’s different it seems . . .
Please let me know if you find any solution!
I have the exact same problem in my project on Unity 2019.1.1f1. I fixed it by using Facebook SDK v7.16.1 instead of v7.17.0. Downloads - Unity SDK - Documentation - Meta for Developers
Hope it’ll help you out too.
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Thanks, I’ll do this until they fix it hopefully in the next update
Hi,
Did using FB SDK v7.16.0 work for you?
Hi,
I did not have time to try this yet, I’ve simply reverted back to our older version of the SDK for the time being.
Facebook SDK 7.17.1 is available, I was hopping that they would have fixed it but after testing it, it gives me the same errors 
So I’ve used v7.16.0 and this version works without any error.
Hopefully this will stop the Facebook alerts I’m receiving to update the SDK.
btw I’ve posted about this problem on the Facebook support board and didn’t get any reply. We can’t be the only ones to get this error …
I have the same problem. I deleted Facebook.Unity.Andorid.dll in the Plugins/iOS folder and deleted Facebook.Unitıy.IOS.dll file in the Plugins/Andorid folder. It causes the problem. It removes the error, by doing that Facebook SDK works now without any problem at Andorid but not at iOS. That is not the correct way to solve this.
Looks like the Facebook team selected all platforms for both Android and iOS libs by mistake in 7.17.1.
To fix the issue just select only one platform for Facebook.Unity.Android.dll and Facebook.Unity.iOS.dll files in FacebookSDK\Plugins\Android and FacebookSDK\Plugins\iOS folders. Both files in Android folder should use Android platform and files in iOS folder should use iOS platform.
Here is a screenshot:
The error message is self-explanatory: Multiple precompiled assemblies with the same name Facebook.Unity.Android.dll included for the current platform.
