Argument out of range - 2 year old project

Receiving an Argument out of range exception for a 2 year old project that has never thrown this before. I simply highlight my mouse over a Unity UI element and it throws the error.


  • Unity 2018.4.17f1
  • Note that I’m able to highlight other
    UI elements and start the game (even
    mess with credits). If I resume
    play it continues like before without
    issue.
  • The only thing that I can think of
    that has changed is that I tried
    copying the folder to a new location
    on a separate drive, but I’ve since
    gone back to the original project
    location once this showed up.
  • I have tried adjusting my layout, as
    this shows up as a way to resolve it
    in older posts
  • Should I delete any meta data
    associated with this object to try
    and refresh it?

ArgumentOutOfRangeException: Argument is out of range.
Parameter name: index
System.Collections.Generic.List1[UnityEngine.EventSystems.EventTrigger+Entry].get_Item (Int32 index) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Collections.Generic/List.cs:633) UnityEngine.EventSystems.EventTrigger.Execute (EventTriggerType id, UnityEngine.EventSystems.BaseEventData eventData) (at C:/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/EventSystem/EventTrigger.cs:212) UnityEngine.EventSystems.EventTrigger.OnPointerEnter (UnityEngine.EventSystems.PointerEventData eventData) (at C:/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/EventSystem/EventTrigger.cs:223) UnityEngine.EventSystems.ExecuteEvents.Execute (IPointerEnterHandler handler, UnityEngine.EventSystems.BaseEventData eventData) (at C:/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/EventSystem/ExecuteEvents.cs:22) UnityEngine.EventSystems.ExecuteEvents.Execute[IPointerEnterHandler] (UnityEngine.GameObject target, UnityEngine.EventSystems.BaseEventData eventData, UnityEngine.EventSystems.EventFunction1 functor) (at C:/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/EventSystem/ExecuteEvents.cs:261)
UnityEngine.EventSystems.EventSystem:Update() (at C:/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/EventSystem/EventSystem.cs:377)

Whew, solved it. I had forgotten I tried adding a new script to the button to fade it, but never really finished the script so it was throwing the error. Simply removing this fixed the issue. I got to the solution by slowing rebuilding the button to see what broke.

I do wish the error was not so vague and actually pointed to the problem…but whatever, time to update my game on Steam.