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If you are going to let others use your computer, the best way to keep all of your data private and secure is to log out of your user account and enable the guest account on your Mac. Here's how
macOS Sierra: Set up users, guests, and groups on your Mac
If your Mac has multiple users, you should set up an account for each person so each can personalize settings and options without affecting the others. You can let occasional users log in as guests without access to other users’ files or settings. You can also create groups. You must be an administrator of your Mac to perform these tasks.
Let occasional users log in as guests
You can let other people use your Mac temporarily as guest users without adding them as individual users. You can use parental controls to set restrictions so guests can access only items that you want to share.
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Guests don’t need a password to log in.
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Guests can’t change user or computer settings.
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Guests can’t log in remotely when remote login is turned on in Sharing preferences.
Files created by a guest are stored in a temporary folder, but that folder and its contents are deleted when the guest logs out.
Guest access works with the Find My Mac feature of iCloud to help you find your Mac if you lose it. You can locate your Mac if someone finds it, logs in as a guest, and then uses Safari to access the Internet. See Use Find My Mac.
Note: If FileVault is turned on, guests can only use Safari and can’t access your encrypted disk or create files.
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Choose Apple menu > System Preferences, then click Users & Groups.
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Click the lock icon 
to unlock it, then enter an administrator name and password.
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Select Guest User in the list of users.
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Select “Allow guests to log in to this computer.”
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If you like, select “Enable parental controls,” then click Open Parental Controls. For more information, see Set up parental controls.
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To let guests use your shared folders from another computer on the network, select “Allow guest users to connect to shared folders.”
Enjoy your day!
