I came across this bug and was able to reproduce it easily, debug logs mailed. My setup: Win7 BTSync 1.4.83 Beta, Android (moto x) app 1.4.50.0. Here's the scenario: Started with a new file on desktop. Waited until all changes mirrored successfully on phone. -> ok. Made edit on phone. Waited until all changes mirrored successfully on desktop -> ok. Made new edit on desktop. Changes overwritten by out-of-date phone version! One possible clue: The time stamps on my phone and computer differ, with the phone ahead by about 2 minutes. If device time-stamps were being used to judge the "newer" file, than the faulty behavior makes sense: The phone still has the "newer" file, because I made the desktop edit in the duration where desktop time was still behind the timestamp of the phone edit. Keep in mind asking the user to have perfect time synchrony between devices is almost impossible. In my case, Windows is setup to automatically synchronize with the 'time.windows.com' server, and similarly, my phone is also setup to use the network provided time. If there's confusion about the newer version of a file, it should be flagged and manually dealt with. Silently overwriting user information is never the correct answer. BTW, bug aside, I quite like the program. Easy to setup, nice UI (Better than owncloud, which I also set up and chose BTSync over) Wish we could choose folder pairs on the android app, instead of being restricted to one download folder, but I understand Android restrictions may play a part there (if not, give us a choice!)