You are removing an element from the group which is involved in a sketch or family constraint with another element of the same group.
Either remove the constraint or cancel the removal of this element from the group.
Namespace: Autodesk.Revit.DB
Assembly: RevitAPI (in RevitAPI.dll) Version: 26.2.0.0 (26.2.0.0)
Syntax
C#
public static FailureDefinitionId RemoveGroupSketchConstraintParent { get; }