How to disable Adobe Core Sync app on OS X from being launched automatically?
You can disable this Finder Sync extension from the System Preferences → Extensions pane (grey puzzle piece icon) – just untick Finder under the app name in question.
Then log out and back in (or restart if you have more than one user logged in to your Mac)


In OS X, the Finder Sync extension point lets you cleanly and safely modify the Finder’s user interface to express file synchronization status and control. Unlike most extension points, Finder Sync does not add features to a host app. Instead, it lets you modify the behavior of the Finder itself.

Extensions are parts of an app that are able to integrate with certain core components of the OS. Finder Sync extensions in particular enable tighter integration with Finder by way of sync status badges, and allowing buttons to be added to the toolbar, sidebar, and right click menus.
OS X keeps a database of all known apps on your computer, and this also includes any extensions (.appex bundles). When Finder launches, it queries this database for Finder Sync extensions and launches them. For security reasons, each extension lives in its own process.