I am trying to calculate statistics on a referenced mosaic dataset in ArcMap 10.2. It is references a selection from a normal mosaic dataset in the same file gdb which contains DTED elevation data. Trying to calc statistics in ArcMap, ArcCatalog, and through a Model Builder exported Python script all return Error: 999999, Failed to execute (CalculateStatistics). I have rights to the folder and there is plenty of disk space. The script runs all the way to 100% before failing.