I got this error: Assertion failed on expression: 'm_CachedAnimator == NULL'

Im getting this error " Assertion failed on expression: ‘m_CachedAnimator == NULL’ " while in Editor each time I select a prefab consisting of a skinnedmeshrenderer component with a mesh I previously duplicated by Instantiate the mesh from a skinnedmeshrenderer component of an imported model.

When I hit play I get this error some times. Im not sure why Im getting this error, my guess is that It has problems showing the preview object in the bottom window when selecting the prefab as I cant see anything there when one of those prefab is selected.

I got the solution by reading this thread finding the cause for a null reference exception
restarting Unity solve the issue.

Bug tracker :