Remote control of another computer

Remote control of another computer is possible using a variety of software, some free, some chargeable.

Screen sharing using Apple's chat program Messages is the easiest to set up, but has limitations compared to its brother app "Screen Sharing". Both are free. Although there are paid applications that you can use, Screen Sharing is reliable and probably does everything you need.

Messages

Between two Macs, Messages can be used to share the screen. See http://support.apple.com/kb/PH15056

In older versions of the Mac software, use iChat. Start an iChat session, click the button at the bottom that looks like two rectangles, have the other person accept.

Screen sharing

A user can access "Screen Sharing" by starting a vnc:// connection in a web browser or "Connect to Server" window. Enter the other user's IP address. Dragging the vnc URL to the dock allows a user to reach, say, a relative's desktop with one click.

If the person being helped is a long distance away, or abroad, it's important to be able to do maintenance without being in physical control of the computer. Sometimes it may be necessary to ask the other person to assist with physical tasks such as reconnecting USB devices or insert CDs, but everything else can be done by remote control.

Screen Sharing is a fairly reliable application, and you shouldn't have too many connection problems once you have your firewalls and routers configured properly. But if you do have difficulty connecting, it could be due to a number of factors, some of which follow. If the remote user disables the Screen Sharing service, you will not be able to connect. If the remote computer is asleep and not connected to the internet via ethernet, there is no way to remotely wake the computer from sleep. If either computer is engaged in heavy internet or CPU activity, Screen Sharing can be so slow as to be unusable. If settings in the router, modem, or firewall have been changed, it may affect Screen Sharing. Therefore, basic troubleshooting involves making sure both computers can connect to the internet, making sure you are using the current IP address of the remote computer, and restarting devices (the remote computer, the local computer, routers).

With Snow Leopard, Screen Sharing works better than it did with Leopard. There is a weird and startling bug that allows the remote user to move your mouse around your screen if you enter Exposé.

Some alternatives

• LogMeIn.com is great and allows a free trial. When it expires they'll try and persuade you to pay, but you can continue using it free, just for remote control; what you will not get is file transfer.

• Microsoft Remote Desktop (see also Microsoft Remote Desktop Clients) will work If the other computer has Windows. It is free.

• Apple Remote Desktop can be used to manage Macs on a network, but is not free.

• TeamViewer is free for personal use.

• Timbuktu has a long presence in this field. It was developed by netopia.com but is now owned by Arris. They do not seem to be updating their own website promptly for the latest versions of this product, so see MacUpdate, this Netopia upgrade page and this discussion at the Apple support forum.

• ShareTool is a great remote login tool, using SSH for encryption; not free but works extremely well and allows Bonjour connections to other systems on the remote LAN.

• Back To My Mac is a macOS feature for screen and file sharing between two Macs that are signed in to the same iCloud account. It was introduced in 2007 but only worked under some conditions. It will no longer be supported under macOS 10.14 Mojave. See this 2018 column in TidBITS.

Just viewing

• Skype has a Share button, which enables you to show the other person all or part of your screen. However, this is just viewing, not remote control.
• Freebinar allows one or more (up to 150) people to watch, and is free.

Precautions

If you have to give someone access to your computer but are worried about security, then:

• give them only screen sharing access (not invisible access like file sharing and remote login)
• make sure your keychain and password storage files are locked
• watch what they are doing the whole time.

When they are done,

• turn off screen sharing
• then change the access password (in that order!)

Never leave remote login turned on if the machine has weak (or blank) user passwords.

Credits

• Contributed by several people in a Mac-Min email thread on February 26, 2010, and since expanded