Problem with file

While doing research for another problem, I noticed these entries in controller.log which do occur every 10 seconds:

[07/30/16 10:01:50] seafile-controller.c(117): bad pidfile format: /opt/seafile/pids/ [07/30/16 10:01:50] seafile-controller.c(399): failed to read pidfile /opt/seafile/pids/ Success

Looking in /opt/seafile/pids there is a file but it’s size is 0.
What to do?

Thanks and best regards,

Edit: Already mentioned here:

Edit2: Removed empty .pid-file and restarted seafile. Works now, new file was created with pid inside. Anyway, since I don’t know how this happened, the controller should handle this normally.