When a coupled analysis solution is started by any method, System Coupling writes a System Coupling Solution Lock file (sycSolve.lock) to its working directory.

This file remains in the working directory and disables the Save, Solve, and any of the Open or Step operations while the solution is in progress, preventing other instances of System Coupling from interfering its execution.

When the solution stops, whether naturally (for example, a completed solution, the end of a script, or an Interrupt or Abort operation) or via a handled exception, the Solution Lock file is removed from the working directory.