The following error
Code:
NullReferenceException: Object reference not set to an instance of an object
Opsive.UltimateInventorySystem.Core.AttributeSystem.RequiredItemDefinitionAttributeCollection.GetInheritOfAttribute (Opsive.UltimateInventorySystem.Core.AttributeSystem.AttributeBase attribute) (at Assets/Opsive/UltimateInventorySystem/Scripts/Core/AttributeSystem/RequiredItemDefinitionAttributeCollection.cs:90)
Opsive.UltimateInventorySystem.Core.AttributeSystem.AttributeBase.GetInheritAttribute () (at Assets/Opsive/UltimateInventorySystem/Scripts/Core/AttributeSystem/AttributeBase.cs:439)
Opsive.UltimateInventorySystem.Core.AttributeSystem.Attribute`1[T].GetInheritedValueInternal (Opsive.UltimateInventorySystem.Core.AttributeSystem.Attribute`1[T] relativeAttribute, System.Boolean checkIfPreEvaluated) (at Assets/Opsive/UltimateInventorySystem/Scripts/Core/AttributeSystem/Attribute.cs:144)
Opsive.UltimateInventorySystem.Core.AttributeSystem.Attribute`1[T].GetValueInternal (Opsive.UltimateInventorySystem.Core.AttributeSystem.Attribute`1[T] relativeAttribute, System.Boolean checkIfPreEvaluated, System.Boolean checkIfBound) (at Assets/Opsive/UltimateInventorySystem/Scripts/Core/AttributeSystem/Attribute.cs:352)
Opsive.UltimateInventorySystem.Core.AttributeSystem.Attribute`1[T].GetInheritedValueInternal (Opsive.UltimateInventorySystem.Core.AttributeSystem.Attribute`1[T] relativeAttribute, System.Boolean checkIfPreEvaluated) (at Assets/Opsive/UltimateInventorySystem/Scripts/Core/AttributeSystem/Attribute.cs:151)
Opsive.UltimateInventorySystem.Core.AttributeSystem.Attribute`1[T].GetValueInternal (Opsive.UltimateInventorySystem.Core.AttributeSystem.Attribute`1[T] relativeAttribute, System.Boolean checkIfPreEvaluated, System.Boolean checkIfBound) (at Assets/Opsive/UltimateInventorySystem/Scripts/Core/AttributeSystem/Attribute.cs:352)
Opsive.UltimateInventorySystem.Core.AttributeSystem.Attribute`1[T].GetVariantValue () (at Assets/Opsive/UltimateInventorySystem/Scripts/Core/AttributeSystem/Attribute.cs:320)
Opsive.UltimateInventorySystem.Core.AttributeSystem.Attribute`1[T].ReevaluateReturnValue (System.Boolean setAsPreEvaluated) (at Assets/Opsive/UltimateInventorySystem/Scripts/Core/AttributeSystem/Attribute.cs:288)
Opsive.UltimateInventorySystem.Core.AttributeSystem.Attribute`1[T].ReevaluateValue (System.Boolean setAsPreEvaluated) (at Assets/Opsive/UltimateInventorySystem/Scripts/Core/AttributeSystem/Attribute.cs:278)
Opsive.UltimateInventorySystem.Core.AttributeSystem.AttributeCollection.ReevaluateAll (System.Boolean setPreevaluate) (at Assets/Opsive/UltimateInventorySystem/Scripts/Core/AttributeSystem/AttributeCollection.cs:489)
Opsive.UltimateInventorySystem.Core.AttributeSystem.AttributeCollection.CreateNewAttributesIfMissing (Opsive.Shared.Utility.ListSlice`1[T] requiredAttributes) (at Assets/Opsive/UltimateInventorySystem/Scripts/Core/AttributeSystem/AttributeCollection.cs:269)
Opsive.UltimateInventorySystem.Core.AttributeSystem.AttributeCollection.UpdateAttributesToMatchList (Opsive.Shared.Utility.ListSlice`1[T] requiredAttributes, System.Boolean removeAdditionalAttributes) (at Assets/Opsive/UltimateInventorySystem/Scripts/Core/AttributeSystem/AttributeCollection.cs:228)
Opsive.UltimateInventorySystem.Core.ItemDefinition.UpdateAttributes () (at Assets/Opsive/UltimateInventorySystem/Scripts/Core/ItemDefinition.cs:744)
Opsive.UltimateInventorySystem.Core.ItemDefinition.Initialize (System.Boolean force) (at Assets/Opsive/UltimateInventorySystem/Scripts/Core/ItemDefinition.cs:202)
Opsive.UltimateInventorySystem.Storage.InventorySystemDatabase.Initialize (System.Boolean force) (at Assets/Opsive/UltimateInventorySystem/Scripts/Storage/InventorySystemDatabase.cs:259)
Opsive.UltimateInventorySystem.Editor.Managers.DatabaseValidator.CheckIfValid (Opsive.UltimateInventorySystem.Storage.InventorySystemDatabase database, System.Boolean autoFix) (at Assets/Opsive/UltimateInventorySystem/Editor/Managers/DatabaseValidator.cs:97)
Opsive.UltimateInventorySystem.Editor.Managers.MainManagerWindow.ValidateDatabase () (at Assets/Opsive/UltimateInventorySystem/Editor/Managers/MainManagerWindow.cs:475)
Opsive.UltimateInventorySystem.Editor.Managers.MainManagerWindow.OnEnable () (at Assets/Opsive/UltimateInventorySystem/Editor/Managers/MainManagerWindow.cs:243)
UnityEditor.EditorWindow:GetWindow(Boolean, String)
Opsive.UltimateInventorySystem.Editor.Managers.MainManagerWindow:ShowWindow() (at Assets/Opsive/UltimateInventorySystem/Editor/Managers/MainManagerWindow.cs:122)