There was a problem deleting the specified grid raster. If the grid is being accessed by an ArcMap or ArcCatalog session, it will have a file lock placed on it and thus cannot be deleted. A file lock will also occur of the grid folder is being accessed by a system file explorer.
- Check that the specified grid does exist at the location identified.
- Make sure that the grid is not being accessed by another ArcGIS session or being viewed in a file browser.
- Check that you have the appropriate permissions for the workspace.