Joined walls won't clean up in elevation

[patricks]

I have 2 wall types on top of one another. The outer-most finish layer of both wall types matches exactly in material and thickness. When I join the walls, it cleans up perfectly in section. However in elevation, I still see a heavy line between the two walls.

Why is this happening? It's like this on every single condition that occurs in this project.

I believe this file was started in 2009 and I upgraded it to 2010. If I try it in a new 2010 project, it works fine. Could this be the issue?

[cliff collins]

Think this may have something to do with it?

From RAC 2010 Documentation:

■ In Revit 2010, multi-threaded methods for printing and wall join cleanup have been made available.
Multi-threaded hidden line removal for printing has been enabled by default.
■ Due to the operating system overhead of maintaining multiple threads, multiprocessing of wall join
cleanups can experience a minor degradation when only 2 CPU cores are present, but up to a 27%
performance increase when 4 hyper-threaded CPU cores are present. Because 2 CPU core systems remain
the most common configuration of Revit systems as reported by CIP data, multiprocessing of this features
is OFF by default.
■ To enable multiprocessing for wall join cleanup, add the following entries to the Revit.ini file:
[PerformanceOptimizations]
ParallelWallJoins=ON
■ To disable multiprocessing for wall join cleanup, you may omit any entries in the
[PerformanceOptimizations] section of the Revit.ini file, or explicitly set the state of either one or both
multiprocessing optimizations:
[PerformanceOptimizations]
ParallelWallJoins=OFF
ParallelPrintProcessing=OFF

cheers...........