It looks like there's a bug in xymond_filestore.c where only the basename of XYMONNOTESDIR is being used. I was able to work around it by putting a symlink in slash to the correct location. lrwxrwxrwx 1 root root 31 Jan 31 12:15 /notes -> /usr/lib/xymon/server/www/notes It seems to be an unnecessary "basename" at line 363: sprintf(logfn, "%s/%s", basename(filedir), hostname); expiretime = 0; update_file(logfn, "w", statusdata, expiretime, NULL, -1, seq); notes.log says: 5901 2019-01-31 12:00:30.754527 Storing tests: <all> 5901 2019-01-31 12:00:30.755415 Want msg 1, startpos 0, fillpos 0, endpos -1, usedbytes=0, bufleft=8392703 5901 2019-01-31 12:00:30.755642 Got 115 bytes 5901 2019-01-31 12:00:30.755755 filestore: Got message 1 @@notes#1/davetest.txt|1548964830.739611|127.0.0.1|davetest.txt 5901 2019-01-31 12:00:30.755865 startpos 115, fillpos 115, endpos -1 5901 2019-01-31 12:00:30.755980 Updating seq 1 file notes/davetest.txt 2019-01-31 12:00:30.761499 Child process 5901 died: Signal 6 strace showed: [pid 5901] open("notes/.davetest.txt", O_WRONLY|O_CREAT|O_TRUNC, 0666) = -1 ENOENT (No such file or directory) [pid 5901] --- SIGSEGV {si_signo=SIGSEGV, si_code=SEGV_MAPERR, si_addr=NULL} ---