I have the same problem, but it might be oom (out of memory) killer.
Oom killer kills program when memory is low, each program have scale, higher number- program will be kill first.
To change scale/score you need to find pid of synfig:
2.open terminal and write
and you got pid.
3.you can check oom score of synfig by command
oom score is from -17 to 17.
4.to change score you need to write
sudo echo X > /proc/PID/oom_adj
where X is from -17 to 17 (we want lower so the number must be on minus)
5.and done, you can check if this work by
I found this in page: oracle.com/technetwork/artic … 11807.html