The RunSimulator command seems to trigger an infinite loop in some cases when paired with a propagation step. The attached script is a minimum working example that recreates the problem. This script should be able to run without any changes for the local machine.
Here's the most relevant part of the script:
For context, I am programatically generating GMAT scripts in order to simulate several batches of data in parallel. Some of the batches I need to simulate are for epochs prior to the Spacecraft state epoch, so I have to back propagate first (or else I'll get stuck in another infinite loop). To be safe, I just added a back propagation line to all of the scripts with a duration that would ensure the simulated spans are always later than the current internal Spacecraft epoch. In general, this process has worked – out of ~19 batches, only this one failed. When this problem happened initially, the script ran for just under 24 hours with no visible file output or increased memory usage.
I tried changing settings and removing other parts of the script without success. The only way to resolve the problem is to change the back propagation span to a duration less than 3 days.