Unreconciled layers are new layers that have been added to the drawing or to attached xrefs since the layer list was last evaluated. The layer list is checked for new layers when a command, such as PLOT is used. In new drawings, the layer baseline is created when the drawing is saved or plotted for the first time. When a new drawing is first saved, the layer baseline is created, and all layers present in the saved drawing are considered reconciled (not new). Layers that are added after a drawing is first saved are considered new unreconciled layers.
When a command that is set in the LAYERNOTIFY system variable is used, the layer list is checked at that time and compared to the baseline. If there are new layers, the Unreconciled Layers layer group is automatically created and activated in the Layers palette.
Unreconciled layers become reconciled by using the Reconcile option of the -LAYER command. Once a layer has become reconciled, it is removed from the Unreconciled Layers layer group. After all new layers are reconciled, the Unreconciled Layers layer group is removed.