If you have multiple users that might have Lightroom open at the same time DO NOT!!! use BTSync for The Lightroom database file. I just lost 2 days of work because 2 users had the same catalog open. This is not an issue with BTSync but user error, and I don't want anyone else to run into the same issue. I have not found a solution to the problem but PLEASE DON'T make the same mistake I did. If anyone has a solution to use BTSync with Lightroom please share. I also want to thank the Bittorrent developers, i love every aspect of your product. It has made my life so easy managing files on 3 Macs / 2 Windows Machines / 1 Linux Server. please keep up the good work. I wonder if it would be worth not allowing .lrcat/.lrdata to be backed up just to save users the same issue. Just a thought.