Code inspection: Boxing is not supported

Unity's Burst compiler does not support boxing value types into object or interface references. This can happen when a struct or primitive is implicitly converted to object, passed to an API that expects object, or otherwise treated as a managed reference.

Example

In this example, the value integer is assigned to an object variable inside a Burst-compiled job. This operation requires boxing and is not supported.

                using Unity.Burst;
                using Unity.Jobs;

                [BurstCompile]
                public struct ExampleJob : IJob
                {
                    public int value;

                    public void Execute()
                    {
                        // Reported: Boxing operations are not supported in Burst
                        object boxed = value;
                    }
                }
            

                using Unity.Burst;
                using Unity.Jobs;

                [BurstCompile]
                public struct ExampleJob : IJob
                {
                    public int value;

                    public void Execute()
                    {
                        // Keep the value in its original unmanaged form
                        int copy = value;
                    }
                }
            

Quick-fix

This inspection does not provide a dedicated quick-fix. Fix it manually by removing the boxing conversion and keeping the code on Burst-compatible unmanaged types.

26 March 2026