Unable to terminate process by kill -9

I assume that you are trying to kill pis 17564 by kill -9 17564

However it is already dead, shown by ts name being in () in the ps output. (I learnt this as being a zombie process but that seems not to be correct but the solution is the same) It will go away when the process that started it reads its exit code.

The man page for ps says that state E means that the process is trying to exit. The command shown is actually the ucomm (accounting) keyword as the system can't find the actual arguments.

To remove the process the process that calls it has to read its exit code, however there has probably been a failure and it won't do that, so you have to kill the parent process.

ps -ajx will show the status and parent - note that Apple/BSD changed the parameters of ps in Tiger and ps -aux does not work ps aux sees a hack as that is what everyone uses. So you need to read the man page.

Having just had this problem with WhatsApp Desktop, for me it seems it was crashpad_handler that was stuck.

ps alx | egrep '[ /](PID|What)' (What being a part of the process name) returned 2 entries: the stuck process & the crashpad_handler for that process.

kill -9 PID of the crash handler took care of the problem in my case. YMMV of course :)