Combine tool failes when combining more than 2 sliced rasters

Question

I am trying to combine total 12 raster out of which 7 are suitabilities, since they are only 9 category, I need to reclassify my suitability in to more units. I used slice tool to reclassify them using 1000 units of equal_area, However if I combine all of these together it gives me a generic error 9999999. or sometimes even something like this message.
ERROR 999999: Error executing function.
("esriDataSourcesRaster.RasterCalcUniqueValues") Too many unique values
ERROR 010159: Unable to open VAT file of C:\Users\Shivani\Searches\Documents\ArcGIS\Default.gdb\Combine_Slic2.
ERROR 010067: Error in executing grid expression.
Failed to execute (Combine).

If i combine using unsliced suitability rasters with my other inputs, the combine tool works perfect and gives me an output raster with all the input values. I tried joining two sliced raters and it worked, but if I try for all 7 rasters together for just sliced inputs, it fails. However I need to allocate future population which means more area will be required as input. I tried using raster calculator for suitabilities like
suitability*100 for changing the input raster value too, it combines two raters, but fails to do all together.
I am stuck for now.
Any help in this regard shall be highly appreciated.

Thanks
Sa

ShivaniAserkar · Answer

Thanks jeff

Appreciate your reply, my combine did worked with your suggestions, here is something I learned in addition, I had exported all my rasters in one geodatabase in GRID format which made combine work in addition to your suggestions. Thanks a lot for your help.

JeffreySwain · Answer

After talking up this incident with a colleague, I also wanted to make a few recommendations.
1.Increase the number of unique values that can exist for a raster under the Customize > ArcMap Options > Raster > Raster Dataset > Unique Values
2. Change the output format to an ESRI GRID (instead of a file geodatabase) 
3. Be sure each of the rasters have an attribute table to them, by running the Build Raster Attribute Table.

JeffreySwain · Answer

Perhaps trying a smaller section (smaller extent) would allow the process to complete.  Because the error message indicates you are exceeding the hard coded maximum for unique values you must find a way to limit it.  I would try to clip your 'equal area' rasters down to a smaller size to see if the process completes then.

As per your requesting an Esri Employee, the quickest way to get a response is to create a Support Incident, as always.