Working together on a project for work or school, looking at a computer screen over someone’s shoulder can grow tiring very quickly. The same goes for trying to help someone with their computer. If we’re only talking about a minute or two, you can take a breath and get it over with, but for longer timespans it might pay off to look into alternatives.

Using screen sharing software, you can mirror the image of one desktop on two computer screens. Often, you can even pass control to the spectating computer with the click of a mouse. Usually, this would require downloading and installing third-party software on both computers. What a lot of people don’t realize is that this software is already present on Mac OS X.

Using these free tools and mere minutes of configuration, you’ll be ready to start screen sharing in no time.

Share Your Own Computer Screen

If you want to share your own screen with someone else, you’ll have to enable support for it first. Open the System Preferences pane via the Apple icon in the top-left corner of your screen, or by going through Applications -> System Preferences. Next, open the Sharing tab, under Internet & Wireless.

On the left side of the screen, toggle on the Screen Sharing service. This will allow other people on your network to access your computer screen. This access is limited to certain user accounts on your computer. The only way to view the computer screen is by logging in with the username and password of one of these whitelisted users on the remote computer.

For safety reasons, I would leave this as is. However, if you cannot enter the log-in credentials on the remote computer in person, you can create a new user account on your computer with a different password, and add it to the list.

By default, users that are sharing your screen will also be able to control your mouse and keyboard. Going to Computer Settings will show you two other options. Here you can enable anyone to request permission to control the screen which you then get to approve, or create an additional password that will allow users to take control of the screen without expressively running it by you. Of course, both of these are optional.

Whether you want to leave Screen Sharing enabled around the clock is your call. There’s no real harm in it if you have sufficiently limited access, but you can toggle it on and off when you need it for additional security.

3 Ways To Connect To A Shared Computer Screen

If the other screen has been shared as outlined above, connecting to it is really easy. Just look for the host computer in your finder sidebar. Selecting that computer reveals a Share Screen button that, when clicked, gives you a log-in prompt. Remember, you’ll only be able to connect by supplying user credentials to one of the accounts that has been whitelisted in the System Preferences of the host computer.

If the other computer does not show up in your Finder sidebar, you can still connect to the shared computer screen. In Finder, select Go -> Connect to Server. In the window that pops up, you’re able to manually enter the IP address of the other computer. This IP address is also visible in the Sharing preference pane on the other computer. Using the vnc:// prefix tells Mac OS X what you’re trying to do, and will fire up the screen sharing application as usual.

As a final resort, you can open the Screen Sharing application directly, even though it’s slightly hidden away on your computer. In Finder, select Go -> Go To Folder, and enter /System/Library/CoreServices.

You can find the Screen Sharing application in this folder. For ease of access, you may want to create an alias from the application to your Applications folder. However, do not move the application itself. This is a system folder of Mac OS X, and you should leave it the way it is.

Have you ever used screen sharing applications on your Mac?  What has been your experience with them?