As part of the Messages app in macOS, it is possible to establish a remote desktop session where you have control of a Mac across the Internet or someone else has control over your Mac desktop. What's more, as well as being simple to get going, it also doesn't require any real installation of extensions or other components.

What does Messages' screen sharing feature do? When a screen share is initiated, the screen from the Mac being controlled will be streamed as a live video feed to the other participant, the Mac that will be used for control. This will allow the user on the controlling Mac to see what is on the desktop of the Mac being controlled. At the same time, a FaceTime Audio call is started between the two users, providing two-way audio. This enables the users to speak to each other, such as advising on what they are doing for the other user or additional instructions. The feature doesn't automatically enable the ability to remote control the other person's display by default, but the option is presented. If control isn't provided by one party to the other, the screen is shared but it is not remotely controllable.

To share your screen with another user:

• Open Messages on your Mac.

• Select the conversation with the person you want to share the screen with. If no prior conversation exists, send a message to them.

• In the main menu, select Conversations then Invite to Share My Screen. The sharing and audio call will begin automatically once the remote user accepts the invitation.

To request another user shares their screen:

• Open Messages on your Mac.

• Select the conversation with the person you want to share the screen with. If no prior conversation exists, send a message to them.

• In the main menu, select Conversations then Ask to Share Screen. The sharing and audio call will begin automatically once the invitation is accepted.

Once sharing is enabled, a new window appears called Screen Sharing, which will host the call and show the sharing user's desktop. There are also some options within the window that can be used. Clicking the mouse pointer icon in the menu will send a request to the sharer to enable remote control of the Mac. Clicking on the remote display will highlight elements on the shared Mac, which can be useful for pointing out elements of an app's interface without taking control. When you have control of the remote Mac, you can also control the Clipboard, which means you can copy and paste text and images between the two computers. This is handy to save you from retyping a URL into a remote browser when you have the link locally. You can even transmit files from the remotely-controlling Mac to the shared Mac by dragging and dropping them onto the window.

To end a screen sharing session:

• For the screen-sharing Mac, click the Sharing icon in the menu bar then End Screen Sharing. Alternately, you can select Pause Screen Sharing if you want to stop for a while.

• The remote controlling Mac can do the same by selecting Screen Sharing in the menu followed by Quit Screen Sharing.

If screen sharing doesn't work, make sure the user of the Mac being shared is signed in to iCloud on that Mac using the same Apple ID that they are using for messages. If they are using different IDs, add both Apple IDs to the same contact within the Contacts app and try again. Also, make sure that they are not limited by Screen Time. If one party is restricted and the initial Messages communication cannot be established, that could prevent Screen Sharing from functioning properly.

• Launch Contacts
• Go to the File menu, scroll down to Export, then choose "Contacts Archive..."
• Name the backup something meaningful and export the .abbu file to the desired location

The resulting .abbu file is easy to reimport by going to File > Import in Contacts. This file can be stored for back up purposes or used if you just want to easily copy Contacts data to a new Mac.

What about iCloud? If you use iCloud, Contacts will synchronize its address book automatically with the cloud. This means you do have a separate copy of all your contacts there, but changes you make locally are synchronized. If you lose contacts locally, the synchronized copy at iCloud may have dropped them as well. Note that you can restore iCloud contacts to a previous state, however:

• Open iCloud Settings at iCloud.com
• Follow the Restore Contacts link under Advanced
• Click Restore next to the most recent backup copy you suspect to contain the lost data

iCloud will create a new backup copy of the current state of your address book (which you can restore using the same process), then replace all contacts on all your devices and iCloud.com with the archived copy.

Here's all you need to do to stick a Note on the Mac desktop:

• Launch Notes app in OS X and double-click the Note you want to tear off
• Position the floating note on the desktop and then close the primary Notes app window

Super simple to get the Note onto the desktop, but now for best part:

• Grab an iPad, iPod touch or iPhone and launch Notes app
• Locate and edit the same note, it will automatically sync and update on the OS X desktop