Jeff thank you for your response,
In m y case I did generate the overviews , and I am actually not publishing my mosaic datasets into a server I'm simply trying to use it in Arcmap. I have been getting this white areas on my overviews, so when I zoom in to the raster. the raster image doesn't have any white areas. I did calculate statistics, and build pyramids prior to building my overviews and my mosaic dataset contains approximately over 5000 rasters(*.ecw).
So i went ahead and removed the rasters where the white areas appears and syncronized Mosaic dataset to update the overviews, so now I have black areas. so i am wondering if I add the removed rasters back to the mosaic dataset will it fix my overviews ??? for the affected areas.
so what's the best way to go about. i have been creating/deleting mosaic datasets, and testing few things but to no avail.