Like any other data type, you can delete a mosaic dataset by right-clicking on it within the Catalog window, and choosing Delete. However this simply deletes the mosaic dataset from the geodatabase. All of the associated files and tables that are related to this mosaic dataset (such as overviews of the mosaic dataset and the item cache) are not deleted.
How do I delete a mosaic dataset and all its related files?
Starting at ArcGIS 10.1, the Delete Mosaic Dataset geoprocessing tool was introduced that provides an option to delete the overviews of the mosaic dataset and the item cache associated with every item of the mosaic dataset.
This tool can be launched from the geoprocessing toolbox (Data Management Tools -> Raster -> Mosaic Dataset toolset) or by choosing “Delete All” from the “Remove” context submenu.
NOTE: Since a referenced mosaic dataset does not have its own overviews or item cache, these options are disabled.
Submitted by: Amit Jain