Here is the important part of the log: [2014-03-31 18:30:15] total physical memory 4294967295 max disk cache 33554432 [2014-03-31 18:30:15] Using IP address 10.1.1.101 [2014-03-31 18:30:15] test sha1: AE5BD8EFEA5322C4D998... [2014-03-31 18:30:15] test sha2: 630DCD2966C4336691125448BBB2... [2014-03-31 18:30:15] test aes: 0A940BB5416EF045F1C39458C653EA5... [2014-03-31 18:30:15] Loading config file version 1.3.67 [2014-03-31 18:30:15] SyncFolderScanner: Adding notifier "\\?\C:\Users\B\Desktop\Test" [2014-03-31 18:30:15] Loaded folder \\?\C:\Users\B\Desktop\Test [2014-03-31 18:30:15] SyncFilesController: started periodic scan [2014-03-31 18:30:15] SyncFilesController [file updated]: Processing file \\?\C:\Users\B\Desktop\Test\Text-File.txt 1396278971 10 [2014-03-31 18:30:15] SyncFilesController: finished periodic scan, checking for missing files [2014-03-31 18:30:15] SyncTrashFolder: Sync trash scan for folder "\\?\C:\Users\B\Desktop\Test\.SyncArchive" started, max file age = 30 days [2014-03-31 18:30:15] SyncTrashFolder: Sync trash scan for folder "\\?\C:\Users\B\Desktop\Test\.SyncArchive" finished [2014-03-31 18:30:17] Send ping to peer (0000000000000000000000000000000000000000) for share E29A38A1DC4A1364C1B5D1ABBA7D5C33B766894E: [2014-03-31 18:30:17] ping 37.201.31.13:51041 [2014-03-31 18:30:18] Send ping to peer (0000000000000000000000000000000000000000) for share E29A38A1DC4A1364C1B5D1ABBA7D5C33B766894E: [2014-03-31 18:30:18] ping 37.201.31.13:51041 [2014-03-31 18:30:19] Send ping to peer (0000000000000000000000000000000000000000) for share E29A38A1DC4A1364C1B5D1ABBA7D5C33B766894E: [2014-03-31 18:30:19] ping 37.201.31.13:51041 [2014-03-31 18:30:20] Send ping to peer (0000000000000000000000000000000000000000) for share E29A38A1DC4A1364C1B5D1ABBA7D5C33B766894E: [2014-03-31 18:30:20] ping 37.201.31.13:51041 The next lines are repetitions. After a router reboot (canceling all old UPD connections) the both BTSync doesn't find a way over TCP together.