Looping through two raster folders to perform raster calculation gives ERROR 999998?

Question

Last week I asked Looping through two raster folders to perform raster calculation? about a script to loop through two geodatabases and perform a raster calculation by matching the two rasters up based on their coordinates. This is my post for clarification:

"I have two geodatabases with rasters containing information about "treecover" and "loss". The file names are slightly different but can be matched based on the last 8 characters (the coordinates of each raster granule).See image

I can perform this simple conditional statement using either CON or RASTER CALCULATOR to retrieve all "Loss" data situated on pixels which have a value for "treecover" greater than or equal to 50, with 9999 being assigned as the output value if the statement is FALSE. The output raster is exactly what I want. I just need to do it for 137 pairs of rasters

RASTER CALC STATEMENT: con("treecover raster" >= 50, "Loss raster", 9999)"

The script so far looks like this:

    import arcpy, os, math
... arcpy.CheckOutExtension("Spatial")
... from arcpy.sa import *
... CVR = r"F:\Work\Aquifers_recalc\Final_recalc\Continent_Data\TEST\Treecover_TEST.gdb"
... LSS = r"F:\Work\Aquifers_recalc\Final_recalc\Continent_Data\TEST\Lossyear_TEST.gdb"
... # get first set of rasters
... arcpy.env.workspace = CVR
... cvr_rasters = arcpy.ListRasters()
... cvr_rasters = [os.path.join(CVR, r) for r in cvr_rasters]
... 
... # get second set of rasters
... arcpy.env.workspace = LSS
... lss_rasters = arcpy.ListRasters()
... lss_rasters = [os.path.join(LSS, r) for r in lss_rasters]
... 
... arcpy.env.workspace = r"F:\Work\Aquifers_recalc\Final_recalc\Continent_Data\TEST"
... for cvr_ras, lss_ras in zip(cvr_rasters, lss_rasters):
...     r1 = arcpy.sa.Raster(cvr_ras)
...     r2 = arcpy.sa.Raster(lss_ras)
...     result = Con(r1 >=50, r2, 999)
...     out_name = "loss_{}.tif".format(cvr_ras[-8:])
...     result.save(out_name)

This script worked for two geodatabases with 4 rasters in each, but when i tried it with 9 rasters in each it failed on the 6th with this error. I will need to do this for two geodatabases with 137 rasters in each.

    Runtime error 
    Traceback (most recent call last):
      File "<string>", line 20, in <module>
      File "c:\program files (x86)\arcgis\desktop10.6\arcpy\arcpy\sa\Functions.py", line 269, in Con
        where_clause)
      File "c:\program files (x86)\arcgis\desktop10.6\arcpy\arcpy\sa\Utils.py", line 53, in swapper
        result = wrapper(*args, **kwargs)
      File "c:\program files (x86)\arcgis\desktop10.6\arcpy\arcpy\sa\Functions.py", line 256, in Wrapper
        ["IfThenElse", in_conditional_raster, in_true_raster_or_constant, in_false_raster_or_constant])
    RuntimeError: ERROR 999998: Unexpected Error.

UPDATE: I deleted the pair of rasters causing the issue and the script still fails. It seems like it always fails after 5 pairs of rastes, without completing the 6th.

UPDATE:By adding the loop I recieved this error, but I got 6 rasters this time:

Tool failed in loop: 6 while executing rasters F:\Work\Aquifers_recalc\Final_recalc\Continent_Data\TEST\Treecover_TEST.gdb\Hansen_GFC2015_treecover2000_00N_070W and F:\Work\Aquifers_recalc\Final_recalc\Continent_Data\TEST\Lossyear_TEST.gdb\Hansen_GFC2015_lossyear_00N_090W
Tool failed in loop: 8 while executing rasters F:\Work\Aquifers_recalc\Final_recalc\Continent_Data\TEST\Treecover_TEST.gdb\Hansen_GFC2015_treecover2000_00N_090W and F:\Work\Aquifers_recalc\Final_recalc\Continent_Data\TEST\Lossyear_TEST.gdb\Hansen_GFC2015_lossyear_00N_070W
>>> 

Answer 1

ArcGIS Help description of the error is the following:

This is an operating system error and can indicate different error conditions. These errors are not specifically documented in the ArcGIS Desktop Help system. However, in most cases, the error description provided with the error code can be used to look up additional information on the operating system.

Taking this into account I would try the following things:

• Take a look at the Name restrictions for raster names and make sure all the rasters have valid names. From your previous posts I see you were naming the output ras_calc_con. Maybe it's not the case in your new script but better make sure you are not using the word con. You can see one of the restrictions is:

The word con should not be used.

• This answer suggests installing a patch to fix this bug. From the patch's page:

Issues Addressed with this patch

BUG-000109772 - The Spatial Analyst tools intermittently throw the 999998 error.

BUG-000108977 - The Zonal Statistics tool produces incorrect statistics when an 8 bit value raster is used as input.

• Add a try/except clause to find whether the error is happening always the 6th time you execute the Con tool or if it only occurs to certain rasters. Your loop could look something like this:

for i, (cvr_ras, lss_ras) in enumerate(zip(cvr_rasters, lss_rasters), 1):
    r1 = arcpy.sa.Raster(cvr_ras)
    r2 = arcpy.sa.Raster(lss_ras)
    try:
        result = Con(r1 >=50, r2, 999)
        out_name = "loss_{}.tif".format(cvr_ras[-8:])
        result.save(out_name)
    except RuntimeError:
        print('Tool failed in loop: {} while executing rasters {} and {}'.format(i, cvr_ras, lss_ras))