This layer or table is in a type of workspace that is not editable.
Solution: In some cases, you may be able to export the layer or table to a new geodatabase feature class or shapefile and edit the data. For example, you can receive this warning when attempting to edit .sdc data, which is not an editable format, although you may be able to edit the data as a feature class or shapefile. You also may receive it when attempting to edit certain rasters; if so, you may be able to build a raster attribute table to edit the attribute vales for the raster.