Try running synergy client not as a daemon
I have had the same problem and until I find a better work around try running it with the --no-daemon option.
I know this post is old, just putting this here for anyone else who may encounter this. Example follows.
Format:
./synergyc --name [optional, specify client name to use] --no-daemon [server]
Ie.
./synergyc --name macmini1 --no-daemon macpro1
or
./synergyc --no-daemon macpro1