I’ve been using Synergy to share my keyboard & mouse between my machine and my Windows gaming VM. A very annoying thing I’ve encountered is that in some games, first person shooters mainly, the mouse goes haywire. Barely touching the mouse causes the shooter to look / spin in circles hundreds of times.

I finally found a fix to this, thanks to this post

The solution is to modify the Synergy server configuration and check the box “Use Relative mouse moves” under Advanced server settings. Then, when in the game, hit scroll lock to lock your mouse to that screen. This fixed the hyperactive mouse issue for me!