Have a few ARM based nodes running BitTorrent Sync (btsync) and needed to re-install one of them. Trying to remove it I ended up with my main node (owner) for all my folders to stop connecting to peers or accepting incoming connections. Took me a while to figure out a solution and I couldn't find much about it on the forums or when I googled so I thought I'll share this quick story.
This applies, in my case at least, to the distribution installed via apt-get from YeaSoft. After reading a forum thread about how to remove old and abandoned peers I decided to set the peer_expiration_days setting to 0 to clean the old peer out. So I used the dpkg-reconfigure btsync command and set it to 0. The old peers where cleaned out so I went back to revert the config back to it's original. In the "wizard" it stated that leaving it blank would render the default value of 7 days. So I removed the 0 and saved the configuration. This might have been a mistake on my part but the configuration tool actually seems broken in this distribution.
After doing that I could not set the value via dpkg-reconfigure btsync to anything else and no peers could connect or where contacted. Right after recycling the daemon they showed up for a few seconds and then disconnected. Since I'm running the free, unlicensed version, I can't switch owner of the folders so I had to get this online again. Changing config files didn't matter since they were, as stated in them, overwritten every time the daemon started again.
Finally I downloaded the latest version from the getsync.com website and unpacked it in the temp folder. Looking at the command line used in the /etc/init.d/btsync script I could find what config file it used. So I started the latest version, which have support for "power user options" in the UI, with the same config file parameter. Went in to the UI and changed the peer_expiration_days back to it's original value, there even is a reset value link. Then shot down the process and started the original daemon with init.d and order where restored.