Mac Messages lets you block people and decide who can see you’re online, but exactly how you can go about it varies by account. To find the available settings, follow these steps:
- Open Messages Preferences from the Messages menu.
- Click the Accounts tab and choose the account in which you want to apply privacy settings.
- Click the Privacy tab (if available) within that chosen account to see the settings.
To proactively determine who can see that you’re online and send you messages, choose a privacy level that you’re comfortable with. The options are
- Allow anyone.
- Allow people in my buddy list.
- Allow specific people. (If you make this choice, you have to type each person’s AIM, .mac.com, iCloud.com, or .me.com address.)
- Block everyone.
- Block specific people. (Again, type the appropriate addresses.)
You can also arrange, inside Messages Preferences, to receive a notification whenever you get a message from unknown contacts. Or get a notification when your name is mentioned. Select the appropriate check boxes on the General tab to select these options.
Sometimes you’ll want to take leave of a particular conversation, at least temporarily. If so, click the Details button, and select the Do Not Disturb check box to mute notifications for the given conversation.