Spurious Lines Polygon to Raster

Discussion created by ceumb@stolaf.edu on Jul 28, 2011
Just ran Polygon --> Raster on a large shapefile.  Run took 24 hours but finished with no error messages. 

But, there are 1 raster wide horizontal lines on new raster that was created at seemingly random locations that almost remind me of scratches on a negative. These lines are not apparent in the source shape file that I am converting. 

I've tried using Majority filter to eliminate but with no luck.

Any thoughts on this would be welcome.  Thanks