It is a general suggestion while switching from the “old” FLUKA.
The “old” FLUKA normally stopped with the output file showing where the error is (e.g. I might have a typo on region name). But the new one just give me a return code (e.g. RC=137) with a zero byte .err file and a 7 byte .log file (“Killed\n”).
This error code is not related to an error in FLUKA, but it suggests, that the process of FLUKA was killed by the system (maybe you don’t have enough memory).
Does this happen with any input you try to run?
If you only get this with a specific input, could you share it with us to investigate?
You must be right since the error for this specific case went away after rebooting the machine. I had similar errors before but didn’t save them (of course, why saving wrong files, right?). I will try if I have similar cases in future.