Viewing what's on the screen of another computer—or even controlling that other computer remotely—can be super-handy, for troubleshooting, looking up documents, or running a program you can't run locally.
As with file-sharing, remotely accessing a Mac from another Mac is relatively straightforward. The tools are built into OS X; you turn on screen-sharing in the Sharing preference pane. But setting up screen-sharing between a Mac and Windows PC takes a bit more work, and requires installing some third-party software. The biggest problem: Macs can't share screens with PCs running Windows 7 Home Premium edition.
Share a Mac’s Screen
To connect from a PC to a Mac, you’ll need to install a VNC client in Windows. There are a number of free clients you can choose from, including TightVNC.
After you’ve downloaded and installed a VNC client on your PC, go back to your Mac and open System Preferences. Choose Sharing, and select the Screen Sharing checkbox.
Screen-sharing is now enabled for remote users signing in with the Mac’s administrator name and password. To enable others to share the Mac’s screen, make sure Screen Sharing is still selected and click Computer Settings. Select Anyone May Request Permission To Control Screen and, if you wish, VNC Viewers May Control Screen With Password; if you select the latter, enter a password in the box. Finally, click OK.
Back in the Sharing pane, under Screen Sharing: On, you’ll see a note that displays an IP address in the form of
Make a note of that address.
Back on the PC, give your VNC client that address (but without the
vnc:// in the front). If you have trouble connecting, check your client’s encoding settings: If they’re set to ZRLE, try switching to Hextile. In TightVNC, you’d do that by launching the VNC Viewer, clicking the Options button, and then selecting a different encoding setting from the Use Encoding drop-down menu.
Share a PC’s Screen
To remotely control a Windows machine, you first need to install Microsoft’s free Remote Desktop Connection Client for Mac on your Mac.
Unfortunately, RDC doesn’t work with Windows 7 Home Premium edition; it works only with Windows 7 Professional, Ultimate, and Enterprise editions; if you want to share the screen of a PC running Home Premium, you’re out of luck.
Windows XP Open Control Panel (in Classic view), double-click the System icon, and open the Remote tab. Select Allow Users To Connect Remotely To This Computer. (If you’re using XP Home edition, select the checkbox for Allow Remote Assistance Invitations, then click on the Advanced button and select the checkbox for Allow This Computer To Be Controlled Remotely.)
If you’re logged in as the administrator, and you have a password, click the Apply button. If not, either click the Select Remote Users button to add new users or create new user accounts.
Windows 7 Open the Control Panel (Category view) then System and Security. Under System, click the Allow Remote Access link. In the System Properties’ Remote tab, select Allow Connections from Computers Running Any Version of Remote Desktop. If you’re the administrator of the Windows system, click the Apply button. If not, click the Select Remote Users button to specify which users can log in to control the PC; you may want to create a new user account just for remote control.
Back on the Mac, launch the Remote Desktop Connection app. In the Computer field, type the PC’s IP address or computer name and click Connect. Supply the username, password, and domain. (In XP, the default domain is Workgroup; in Windows 7, use the computer name.)
John Rizzo is the publisher of MacWindows.com and the author of Snow Leopard Server for Dummies (Wiley, 2009).