[LAD] connect(2) call to /dev/shm/jack-0/default/jack_0 failed (err=No such file or directory) (again...)

Hi all, Sorry to bother you again with this. I’m running into the same problem again as before (see the latter part of the [LAD] jackd not using jackdrc… thread). And apparently my last fix involved some magic rather than replicable logic… :-( i.e. the problem seems to have disappeared on that system, without knowing exactly why) Now I am installing my jack client again on another fresh install of ubuntu 17.04. and a get the same error. I have installed jackd1, to be exact, these packages are current. jackd/artful,artful,now 5 all [installed,automatic] jackd1/artful,now 1:0.125.0-2 amd64 [installed] jackd1-firewire/artful,now 1:0.125.0-2 amd64 [installed,automatic] libjack0/artful,now 1:0.125.0-2 amd64 [installed] qjackctl/artful,now 0.4.5-1ubuntu1 amd64 [installed,automatic] when I start my client jackd is automatically started but i get the error: connect(2) call to /dev/shm/jack-0/default/jack_0 failed (err=No such file or directory) By browsing the jack sources i found the message seems to come from libjack/client.c in server_connect() peeking into the /dev/shm directory it seems /dev/shm/jack-0/default/jack_0 is briefly created,but disappears again, presumably just before the client is able to connect. I have been breaking my head over this, but I really have no clue why this is happening, especially as this has worked fine in the past. I would really like to know what could possibly cause this error and how to fix it. thanks, fokke