Getting Compiler Error RVOCoreSimulator.cs in version 4.2.4

Deleted Asset reimported and still getting the following error.

Assets/AstarPathfindingProject/Core/RVO/RVOCoreSimulator.cs(805,13): error CS0433: The imported type `System.Threading.ManualResetEventSlim’ is defined multiple times


Sorry for the late answer.
Which version of Unity are you using? And which exact build settings?

In version 4.2.5 getting the same/simialr error in Unity 2018.3.6f with .Net 4.x Scripting Runtime enabled.The RVOCoreSimulator.cs lines 805 & 806, ManualResetEventSlim exists in both System.Threading and .netstandard if you have .Net 2.0 API Compatibility Level or mscorelib if you have .Net 4.0 Compatibility Level.

Reverting to .Net 3.5 Scripting Runtime Version resolves this.

Is there a fix for this that allows for .Net 4.x? I can’t use an earlier version, but am having this issue.

I’m on the latest 4.2.8