Log files
The server log file is per default located at C:\Program files\UrBackupServer\urbackup.log. Change warn to debug in C:\Program files\UrBackupServer\args.txt to create a debug log file. Debug log files are preferred. The log file on Linux/FreeBSD is located per default at /var/log/urbackup.log. The log level is an argument to the server program (urbackupsrv run -v debug) or can be configured via /etc/default/urbackupsrv or /etc/sysconfig/urbackupsrv.
The client log file is per default located at C:\Program Files\UrBackup\debug.log on Windows. Run C:\Program Files\UrBackup\enable_debug_logging.bat as admin to enable debug logging. On Linux/FreeBSD the client log file is located at /var/log/urbackupclient.log. To enable debug logging run the backend with urbackupclientbackend -v debug or it can be configured via /etc/default/urbackupclient or /etc/sysconfig/urbackupclient.
Attach the log files to your new post or send them to bugreports@urbackup.org, because they may contain data which should not be public.