Unity Heightmap Bug

I recently upgraded to the new unity. I have some assets, textures to be particular. When I click on the height map, i get an error

ArgumentException: May only be called in OnPostProcessTexture
UnityEditor.Modules.DefaultTextureImportSettingsExtension.ShowImportSettings (UnityEditor.Editor baseEditor, UnityEditor.TextureImportPlatformSettings platformSettings) (at C:/buildslave/unity/build/Editor/Mono/Modules/DefaultTextureImportSettingsExtension.cs:93)
UnityEditor.TextureImporterInspector.ShowPlatformSpecificSettings () (at C:/buildslave/unity/build/Editor/Mono/ImportSettings/TextureImporterInspector.cs:1461)
UnityEditor.TextureImporterInspector.OnInspectorGUI () (at C:/buildslave/unity/build/Editor/Mono/ImportSettings/TextureImporterInspector.cs:1305)
UnityEditor.InspectorWindow.DrawEditor (UnityEditor.Editor editor, Int32 editorIndex, Boolean rebuildOptimizedGUIBlock, System.Boolean& showImportedObjectBarNext, UnityEngine.Rect& importedObjectBarRect) (at C:/buildslave/unity/build/Editor/Mono/Inspector/InspectorWindow.cs:1236)
UnityEditor.DockArea:OnGUI()

Help! I CANT WORK WITHOUT THIS ERROR GONE!

I am affraid i have the same problem. Did you figured it out?

I think I reinstalled unity. Cant remember, it was a while ago.