On 2019.8, if I type "mpiexec", I get a help text message. On a new install of 2021.4.0, if I type "mpiexec", it hangs indefinitely. I can ctrl-c twice to get out of it, and it traps the SIG by showing:
^C$ Sending Ctrl-C to processes as requested
$ Press Ctrl-C again to force abort
I can't use mpiexec within batch scripts either for the same reason. Why does it hang?