When data is added to ArcMap, the following error message is displayed:
"Warning, inconsistent extent!".
This error message is returned if the data has an incorrect projection definition.
Specifically, the data is in a projected coordinate system with units of feet, meters or other linear units, but the projection has been defined with a Geographic Coordinate System (GCS) that has units in decimal degrees.
Refer to knowledge base article 29129 for information on how to identify the type of coordinate system to which the data is projected.
KB 29129 links to additional articles that contain step-by-step instructions for identifying the specific coordinate system for data that does not have its projection correctly defined.