Question by FerdieKucheza · Mar 19, 2019 at 11:11 AM · exception exceptions

We get this "TypeLoadException: Could not load type UnityEngine.UI." after every compile

We get these weird two TypeLoadException error after every compiling of our code. One for UnityEngine.UI.Scrollbar (first one) and one for UntiyEngine.UI.Slider (second one). Our code worked perfectly before and we haven't changed anything to the UI or whatever, just implemented some external API.

TypeLoadException: Could not load type UnityEngine.UI.Scrollbar, UnityEngine.UI, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null while decoding custom attribute: (null) System.MonoCustomAttrs.GetCustomAttributesBase (System.Reflection.ICustomAttributeProvider obj, System.Type attributeType, System.Boolean inheritedOnly) (at :0) System.MonoCustomAttrs.GetCustomAttributes (System.Reflection.ICustomAttributeProvider obj, System.Type attributeType, System.Boolean inherit) (at :0) System.RuntimeType.GetCustomAttributes (System.Boolean inherit) (at :0) UnityEngine.AttributeHelperEngine.GetExecuteMode (System.Type klass) (at C:/buildslave/unity/build/Runtime/Export/AttributeHelperEngine.cs:122) UnityEngine.AttributeHelperEngine.CheckIsEditorScript (System.Type klass) (at C:/buildslave/unity/build/Runtime/Export/AttributeHelperEngine.cs:140)

TypeLoadException: Could not load type UnityEngine.UI.Slider, UnityEngine.UI, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null while decoding custom attribute: (null) System.MonoCustomAttrs.GetCustomAttributesBase (System.Reflection.ICustomAttributeProvider obj, System.Type attributeType, System.Boolean inheritedOnly) (at :0) System.MonoCustomAttrs.GetCustomAttributes (System.Reflection.ICustomAttributeProvider obj, System.Type attributeType, System.Boolean inherit) (at :0) System.RuntimeType.GetCustomAttributes (System.Boolean inherit) (at :0) UnityEngine.AttributeHelperEngine.GetExecuteMode (System.Type klass) (at C:/buildslave/unity/build/Runtime/Export/AttributeHelperEngine.cs:122) UnityEngine.AttributeHelperEngine.CheckIsEditorScript (System.Type klass) (at C:/buildslave/unity/build/Runtime/Export/AttributeHelperEngine.cs:140)

The errors simply go away when the console is cleared, but then re-appear as soon as we enter Play mode. Since the error mentioned custom attributes, we checked if we changed any of our attributes, but that didn't seem like the case.

Yesterday I've encountered similar problems, but the errors were slightly different (I'd receive the "unloading broken assembly unity" error referring to the same UnityEngine.UI.dll). Unfortunately, I didn't get a copy of the text of that...

Some significant data:

Version: Unity 2018.3.9f1
Target platform: Android
Scripting runtime version: .NET 4.X equivalent
Scripting backend: Mono
API Compatibility level: .NET 4.X
We're using a custom DLL (we've got the source code ourselves) to make requests to a WebAPI
Those two DLL-files (a Client.dll and a Models.dll) are integrated into the Plugins folder and have always worked perfectly fine with Unity