OK, solved the issue with reset the permission for users and groups. -> Nevertheless it's strange why this occors. The thing with (very) low transfer speed, was solved by selecting "Search DHT Network" The indexing seems not working proberly. There are 110GB to be indexing... btsync says "indexing" but does nothing. A reboot of the source DS1010 worked (for now). I will reply when this occurs again. @Flow: I don't have an icon, too.