More progress. At first I thought it was a library issue due to the output of ldd but it turns out ldd just wasnt looking in the right place. This command fixed ldd: root@DNS-321:~# export LD_LIBRARY_PATH=/lib:/usr/lib:/ffp/lib which made LDD return: root@DNS-321:/ffp/bin# ldd btsync ldd: can't open cache '/ffp/etc/ld.so.cache' librt.so.1 => /lib/librt.so.1 (0x40002000) libdl.so.2 => /lib/libdl.so.2 (0x4001d000) libm.so.6 => /lib/libm.so.6 (0x40028000) libpthread.so.0 => /lib/libpthread.so.0 (0x400d9000) libc.so.6 => /lib/libc.so.6 (0x400f2000) ld-linux.so.3 => /lib/ld-linux.so.3 (0x40207000) A clue can be given running with the --nodaemon switch root@DNS-321:/ffp/bin# ./btsync --nodaemon ./btsync: relocation error: ./btsync: symbol __res_iclose, version GLIBC_PRIVATE not defined in file libc.so.6 with link time reference Looks like some sort of deep seeded error with glibc. Odd that it would work so well with (presumably) the same version of ffp on a DNS-320 as recorded here: http://forum.nas-cen...hp?f=249&t=8605 . Giving up for now. Will keep watching this thread.