While synching 200 GB(!) with a SAMBA share there were some network errors (semaphore timeout, network path not found) after some hours. FSF then stops and waits for the user to click "repeat". After that click, everything works fine again for some hours. As I cannot locate or fix this network issue at the moment.
It would be nice if FSF handles such situations by itself: On detecting an error it could retry multiple times with some seconds between every retry and log their occurence. If these retries fail, FSF stops and reports the error to the user. This behavior could be switchend on/off in the configuration.