MacOS turn off sync with iPhone for a while Imagine I want to lend my friend my MacBook for an evening when I'm in the same place playing iPhone synced with the MacBook. I don't want him to check/send messages. Is it possible to turn off that functionality for a while?
Create a new user account (or enable the Guest user) on your Mac (System Preferences -> Users and Groups)
Log out of your account
Have your friend log in with the new or the guest account


Using a separate accounts prevents any messages from showing up, it also ensures that nobody will be able to mess with your data.