I run boincmgr 7.6.31 on Ubuntu 16.04 and after the last OS update, boincmgr just crashes. Where is the log file so that I can post the error messages?

/var/lib/boinc/ on my box running 7.12.0 on 18.10 but I have a sneaky feeling it may have changed but I can't remember what from.

Searching these forums would eventually turn up the answer. Also if my system is anything to go by, you will need root access to get into it.

Have you tried starting the manager from a terminal to see what the error message there is?

Yeah, from the command line, it was exiting with a 255 return code. Did some snooping and found that there was a lock file starting with"BOINC Manager-" and username. It contained a pid. I deleted this file and voila, the boincmgr started up. It would be nice if boincmgr just told you another boincmgr is running instead of an error code that's not documented anywhere.