MAXScript can be used in the Every Step and Final Step scripts of the PF_Source and in the Scripted Actions - Birth_Script, Script_Operator and Script_Test.
These scripts are executed very often and in a very special environment, for example, during rendering. This is why it is not possible to use all MAXScript commands with Particle Flow.
Here are some known limitations:
You cannot reset 3ds Max from inside a Particle Flow script.
You cannot create a new 3ds Max scene.
You cannot open an existing.MAX file.
You cannot merge a MAX file with the current scene.
You cannot create or delete Particle Flow Operators.
You cannot excessively create objects during the evaluation of Particle Flow scripts (for example inside the on Proceed method).
You cannot delete objects from inside a Particle Flow script.
The MAXScript snapshot as mesh method should not be used during render time (like in the Proceed method), or all objects that the shapshot as mesh method is used upon should be hidden during render, otherwise a crash will occur.