I have to admit that when receiving phone calls on the Mac became a thing under Yosemite, I was pretty excited about the possibility. Oh, sweet naive Melissa from way back when!
Now, though, my feelings on that have changed. The idea that every Apple device I own should ring when someone calls me? Madness, and especially so on my computer. There is, however, a really easy way to turn off that “feature,” thank goodness. To do that, open the FaceTime program from your Applications folder.
Then click on the “FaceTime” menu at the upper-left and choose “Preferences.”
From the window that’ll open, simply deselect the “Calls from iPhone” checkbox.
Moreover, if you want to prevent your Mac from receiving FaceTime calls entirely (like if someone accidentally attempts to start a video chat), go to the top of that window and deselect the “Enable this account” checkbox.
If you’d prefer, you can also pick the “Turn FaceTime Off” option shown in my second screenshot above. But then your Mac will no longer ring, either when your phone does or for mistaken video calls! Ahhhh, sweet, blessed silence.