Facetime comes on automatically when an unknown caller phones

1. Check FaceTime Settings on iPhone and iMac

On iPhone:

1. 1. Open Settings.
   2. Scroll down and tap FaceTime.
   3. Ensure that Calls from iPhone is turned off.

On iMac:

1. 1. Open FaceTime.
   2. In the FaceTime menu, click Preferences.
   3. Make sure Calls from iPhone is unchecked.

2. Disable FaceTime on iMac

If you don’t use FaceTime on your iMac, you can disable it:

1. 1. Open FaceTime.
   2. In the FaceTime menu, click Turn FaceTime Off.

3. Check for Handoff and Continuity Settings

3.Handoff and Continuity might be causing the issue, where your devices are set to work together seamlessly. You can turn off these settings:

On iPhone:

1. 1. Open Settings.
   2. Tap General.
   3. Tap AirPlay & Handoff.
   4. Toggle Handoff off.

On iMac:

1. 1. Open System Settings.
   2. Click General.
   3. Click AirDrop & Handoff.
   4. Toggle Allow Handoff between this Mac and your iCloud devices off.

4. Review Notifications for FaceTime

Check the notification settings to ensure FaceTime notifications are not causing the app to open:

On iPhone:

1. 1. Open Settings.
   2. Tap Notifications.
   3. Scroll down and tap FaceTime.
   4. Adjust notification settings as needed.

On iMac:

1. 1. Open System Settings.
   2. Click Notifications.
   3. Scroll down and select FaceTime.
   4. Adjust notification settings as needed.