Solution or Workaround
Summary
CLEAN, BUILD, MAPJOIN, or any Overlay Module command returns this message:
Assembling polygons...
Unclosed polygon border (ARCPAL)
Cause
This is usually a result of a corrupted MSK file.
Solution
Option 1: Delete the .MSK file from the coverage before using CLEAN or BUILD.
Option 2: Increase fuzzy tolerance by 1.5 or decrease it by .25. Adjust fuzzy tolerance until the situation no longer occurs.
Since MAPJOIN does not have an option for {fuzzy_tolerance}, use the Starter Kit command TOLERANCE to adjust this value in each coverage's TOL file. MAPJOIN uses the value set in TOL to determine the tolerance.