There are some known compatibility issues between tyFlow and other software that can cause 3ds Max to crash during startup:
Prior to tyFlow v1.111, having the Anima plugin installed alongside tyFlow could cause 3ds Max to crash shortly after 3ds Max finished loading (seemingly at random). tyFlow v1.111 introduced some additional measures to prevent this issue from occurring.
Certain versions of CrowdStrike Falcon (enterprise system protection software) can cause 3ds Max to crash if tyFlow is present. The solution is to white-list 3ds Max within CSF, to prevent CSF from interfering with tyFlow’s startup routines.
Startup crashes that don’t fit those criteria should be reported as bugs.
First, ensure that tyFlow isn’t simply running out of available RAM. Run the simulation again, and check the amount of memory that 3ds Max uses with the Windows Task Manager. If 3ds Max gets to the point where it is using all of your available RAM, this can lead to system instability. The easiest way to decrease the amount of RAM that a tyFlow simulation requires, is to disable tyFlow caching. Be aware that if you disable caching, the simulation must be recomputed from scratch each time you wish to play it back.
However, if the crash is not caused by a lack of available RAM, information about what to do if you run into such a bug can be found here.