(Thanks to user SNG for doing some of the leg work here) I think we finally have a working solution for running Bittorrent Sync as a service. One of the features added in 1.4.103 is the ability to run a command line argument "/webui" which sets the default interface to a web page. This feature finally gets us over the finish line and allows for true run as a service under Windows. Prerequisites:Install / Update Bittorrent Sync to at least version 1.4.103 and run the application.Download the latest NSSM (Non-Sucking Service Manager) from http://nssm.cc/ and extract the contents. (I used v2.24) Create a text file in the Bittorent Sync Program Files folder called "btsync.conf" and populate this file with the following lines:{ "device_name": "HOSTNAME", "webui" : { "listen" : "0.0.0.0:8888", "login" : "USERNAME", "password" : "PASSWORD" }} Replace HOSTNAME with the name that you wish to use to identify the Bittorrent Sync instance. Replace USERNAME with the username you wish to use for the WebUI credentials. Replace PASSWORD with the username you wish to use for the WebUI credentials. The "listen" line is important because the WebUI only responds to local loopback by default while 0.0.0.0 allows for response to any host. You may optionally specify an IP to limit responses to that specific host.Installation as a Service: Open a command prompt (with Admin privileges for Windows OSs newer than XP/2003) and change directories into the extracted NSSM folder from step 2.Type "nssm install btsync", and the GUI interface for NSSM will appear.In the "Application" tab, click the ellipse button, browse to the Bittorrent Sync Program Files folder, and select "BTsync.exe"It will populate the "Startup Directory" field, leave this at defaultUnder the "Arguments" field, enter "/webui /config btsync.conf"(optional) Under the "Details" tab, enter "Bittorrent Sync Service Wrapper" in the "Display Name" field.Make sure that "Startup type" is set to "Automatic"Leave all other fields at default and click the "Install Service" button.Make sure to close the instance of Bittorrent Sync if it is currently running in your user session.Open the Services.msc snap-in, select "Bittorrent Sync Service Wrapper", and click start.Open a browser on the same local network, and enter http://HOSTNAME:8888 (where HOSTNAME is the name of the computer). You should be prompted to enter credentials. You're done! You should now be able to manage Bittorrent Sync on the computer without an active user session. I have completed the above procedure on two separate servers (2003R2) and was able to successfully sync data between them, after setting up the folders using Chrome from a third computer.