In the Revit.ini file, settings in the [PerformanceOptimizations] section improve the performance of the software.
ParallelWallJoins
By default, the software uses multi-processing for wall join cleanup on all 64-bit computers.
To disable multi-processing for wall join cleanup, set ParallelWallJoins=OFF.
Note: Turning off ParallelWallJoins may degrade performance. It is recommended that you do not disable this optimization setting.
Examples
[PerformanceOptimizations] ParallelWallJoins=off