Having a similar issue. In my case Jessie Raspbian on RPi 1 fails as well as Jessie OSMC on RPi 2
Case 1 - RPi 1 Raspbian: Tried the method 1 via official repo:
sudo sh -c 'echo "deb http://linux-packages.getsync.com/btsync/deb btsync non-free" > /etc/apt/sources.list.d/btsync.list'
wget -qO - http://linux-packages.getsync.com/btsync/key.asc | sudo apt-key add -
sudo apt-get update
sudo apt-get install btsync
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed:
btsync
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 4,506 kB of archives.
After this operation, 6,786 kB of additional disk space will be used.
Get:1 http://linux-packages.getsync.com/btsync/deb/ btsync/non-free btsync armhf 2.3.8-1 [4,506 kB]
Fetched 4,506 kB in 3s (1,465 kB/s)
Selecting previously unselected package btsync.
(Reading database ... 118183 files and directories currently installed.)
Preparing to unpack .../btsync_2.3.8-1_armhf.deb ...
Unpacking btsync (2.3.8-1) ...
Processing triggers for systemd (215-17+deb8u4) ...
Setting up btsync (2.3.8-1) ...
Job for btsync.service failed. See 'systemctl status btsync.service' and 'journalctl -xn' for details.
invoke-rc.d: initscript btsync, action "start" failed.
dpkg: error processing package btsync (--configure):
subprocess installed post-installation script returned error exit status 1
Processing triggers for systemd (215-17+deb8u4) ...
Errors were encountered while processing:
btsync
E: Sub-process /usr/bin/dpkg returned an error code (1)
Case 2 - RPi 2 running OSMC: Tried the method 1 via official repo: it shows the service started ok and is running but the Web Interface from another host 192.168.x.x:8888/gui/ says "unable to connect"
Case 3 - RPi 2 running OSMC: Also tried method 2 via Rpi armhf deb link I found on this forum.
cd ~/
sudo mkdir Temp
cd Temp
sudo wget https://download-cdn.getsync.com/2.3.8/PiWD/bittorrent-sync-pi-server_2.3.8_armhf.deb
sudo dpkg –i ~/Temp/bittorrent-sync-pi-server_2.3.8_armhf.deb
sudo nano /etc/btsync/config.json
"listen" : "INSERT_YOUR_IP_HERE:8888"
Method 2 fails to install on my OSMC due to expected "pi" user_id. I tried editing the config file but it would still fail to start.
sudo nano /etc/init.d/btsync
BTSYNC_USER=”osmc”
EDIT: I tried dpkg .deb install on Raspbian RPi1 since it has default "pi" user and it is worked. Additional step I needed was to update config.json file to listen on LAN IP and not 127.0.0.1