If you are using the Messages App on Mac, it is important that you remember to Sign out from iMessage, after you are done using the Messages App.
This way you can prevent the possibility of anyone else being able to read your messages, when you step away from the computer and also when your Mac can be accessed by others in the family or place of work.
Another reason for users looking for a way to Sign out from iMessage on Mac is to prevent frequent iMessage notifications from bothering them, while they are busy and trying to get some work done.
Logout from iMessage on Mac
You can find below the steps to Sign out from iMessage on Mac and also the steps to prevent frequent iMessage notifications from bothering you.
If required, you can also prevent iMessages from syncing to your Mac by removing or unlinking your Apple ID from Mac.
1. Sign Out From iMessage on Mac
It is a good practice to sign out from iMessage, if you are leaving for a meeting or stepping away from your Mac for an extended period of time.
1. Open the Messages App on your Mac.
2. Click on Messages tab in top-menu bar and select Preferences in the drop-down menu.

3. On the next screen, switch to iMessage tab and click on the Sign out button.

2. Switch OFF iMessage Notifications
If you are busy working and getting distracted by IMessage notifications, you can follow the steps below to switch OFF iMessage notifications on your Mac.
1. Click on Apple Logo in top-menu bar and select System Preferences in the drop-down menu.

2. On the next screen, switch to Notification tab > select Messages in the left-pane. In the right-pane, move Allow Notifications toggle to OFF position.

After this, you will still be able to send and receive Messages on your Mac, but won’t be bothered by iMessage notifications.
3. Deactivate iMessages on Mac
Another way to take a break from iMessages on Mac is by temporarily deactivating your iMessage Account.
1. Open Messages App > click on Messages tab in the top-menu bar and select Preferences in the drop-down menu.

2. On the next screen, switch to Accounts tab, select your iMessage Account in the left-pane and uncheck Enable this account option in the right-pane.

This will prevent received iMessages from showing up on Mac. At any time, you can go back and enable iMessage on your Mac by checking “Enable this account” option.
4. Prevent iMessages from Syncing on Mac
You can prevent iMessages from syncing on Mac by removing your Apple ID Account from Mac.
1. Open the Safari browser on your Mac.
2. Go to Apple ID page and Login to your Apple ID Account.
3. Once you are logged in, scroll down to “Devices” section > select the Mac that you want to remove from Apple ID and click on Remove from account option.

Once your Mac is removed from Apple ID page, you will no longer find iMessages syncing on your Mac.