By default, after you install the uSync Content Edition nuget package, it will enable the content sycn (both content and media). To disable the auto content sycn, locate file uSyncBackOffice.Config under config folder, and set the following handler to false.

    <HandlerConfig Name="uSync: ContentHandler" Enabled="false" /> 
    <HandlerConfig Name="uSync: MediaHandler" Enabled="false" /> 

Happy Coding! 😇