Mac OS X Yosemite - How to disable the Handoff feature
Apple introduced Handoff, a new continuity feature allowing you to resume tasks started on iOS 8 device directly on your Mac (and vice versa). In this FAQ you will learn how to disable the Handoff feature on Mac OS X Yosemite:
Go to System Preferences > General.
Uncheck "Allow Handoff between this Mac and your iCloud devices".