Jack erros

I’ve installed Jack on my Mint 18.2 and when I start it, I get some error messages:
ERROR: Cannot lock down 82274202 byte memory area (Cannot allocate memory)
ERROR: Cannot use real-time scheduling (RR/10)(1: Operation not permitted)
ERROR: AcquireSelfRealTime error

http://jackaudio.org/faq/linux_rt_config.html

Shoio I would guess you installed jack from a GUI installer either usc or the gnome software app. Neither will install jack correctly. First check for a file in /etc/security/limits.d/ called audio.conf and if it is called audio.conf.disabled… rename it. Take a look inside the file at the last three lines that should all start with @audio or something like that. This is the group your user needs to be a part of (without the @). Some systems may have @realtime instead of audio. In any case you then need to make sure you are in that group as shown in the link Paul gave. then logout and back in to reset your groups.