Apelsin

I'm running Sync 1.3.77 on both Windows 7 x64 systems.

Could you please enable debug logging and share the log here (provided document paths aren't sensitive information?) It's possible you have incompatible/invalid file names: http://forum.bittorrent.com/topic/29136-bug-and-repro-only-first-sync-works-requires-restarting-bt-sync/ Or it could be something entirely different.

I recently abandoned SASS file synchronization in preference of DIY solutions, namely ownCloud and BitTorrent Sync, the latter of which I prefer for its design. I got excited about this and so I set it up on a few of my devices and everything was going just fine with new directories I made for trying things out. I felt ambitious and decided to sync a bunch of my existing files (for which I'd previously used GoodSync across devices). I was synchronizing my pictures folder when I noticed that after the first sync, BT Sync wouldn't continue to update files. I tried fiddling with the folder and advanced settings and I wasn't getting anywhere so I turned on debug logging...to no avail. Nothing stood out and nothing looked like the source of the problem. Then I remembered something: I'd moved a bunch of my pictures from my Mac system onto my (almost exclusively) Windows systems. Windows has restrictions on what characters are allowed in file names and Mac OS has none to my knowledge. Long story short, I ended up renaming two offending files: >@3.jpg