I don't want to share my clipboard between 3 computers I'm sharing with synergy. How do I disable that?
There's an issue in their issue tracker over here: http://synergy-foss.org/tracker/issues/802
The title of the issue is "Option to disable all clipboard sharing" so I think that's what you're looking for.
Unfortunately the issue is 6 years old and just three months ago the version target was deletet. Even though the issue is "accepted" its priority is still "low" so apart from the fact that this feature is not yet available it might take a little longer until it finally will be.