Can somebody figure out whats going on here? I had absolutely no problems running these commands before. I am trying to add 1046 raster layers. I created a list of rasters using arcpy.ListRasters() Then used CellStatistics to "SUM" all the rasters in the list. Error 010240 was generated. Then repeated the procedure for only a few rasters. It worked. Repeated again for all the rasters and the error was generated again. Came back to a few rasters and the error is generated again! Clicking on the error either closes Arc with 'Not enough memory' message or nothing happens. Searching a tool and opening it opens a blank 'Script error' message. I'm using Arc 10.3. I recently installed Point cloud library and CMake and all the other dependencies. Both simple addition by looping and cell statistics are not working in any case now.

>>> ws="E:\Karun\MTech_Project\MB_RasterAnalysis.gdb"
>>> arcpy.env.workspace=arcpy.env.scratchWorkspace=ws
>>> rlist1
    [u'rast_1', u'rast_2', u'rast_3', u'rast_4', u'rast_5']
>>> fr=CellStatistics(rlist1,"SUM")
    RuntimeError: ERROR 010240: Could not save raster dataset to E:\Karun\MTech_Project\MB_RasterAnalysis.gdb\sumco_ras with output format FGDBR.
>>> fr=CellStatistics(rlist1,"SUM")
    RuntimeError: ERROR 010240: Could not save raster dataset to E:\Karun\MTech_Project\MB_RasterAnalysis.gdb\sumco_ras with output format FGDBR.
>>> rlist1[0]+rlist1[1]
    u'rast_1rast_2'
>>> Raster(rlist1[0])+Raster(rlist1[1])
>>> temp=Raster(rlist1[0])+Raster(rlist1[1])
    RuntimeError: ERROR 010240: Could not save raster dataset to E:\Karun\MTech_Project\MB_RasterAnalysis.gdb\plus_ras with output format FGDBR.
>>>