Sharing files, hard drives, and other digital assets between Macs on a network can be simple. Doing so between Macs and Windows machines can be anything but.

While the two platforms each have built-in tools for cross-platform communication, getting those tools to work the way they should requires tinkering. The specifics of that tinkering depend on the versions of Windows and OS X you’re using.

For the purposes of this article, we’ll assume you’re using OS X 10.5 or 10.6. We’ve provided separate instructions for Windows XP and Windows 7; the latter should work in the Home Premium, Professional, and Ultimate editions. The one exception is that screen-sharing doesn’t work in Home Premium. We also assume that your Mac and Windows machines are already successfully connected to a home network and are visible to one another.

By installing Remote Desktop Connection on a Mac, you can remotely control a PC running Windows XP or Windows 7 (but not the Home Premium edition).

Share a Mac’s files
Configuring your Mac to let Windows users access its folders isn’t that different from doing so for other Mac users: you tell OS X which folders you want to be accessible and then set permissions for them.

On your Mac  Start by opening the Sharing pane in System Preferences. Click the lock icon at the lower left and enter your administrator password to unlock it (if necessary). Then select the File Sharing checkbox. With File Sharing still selected, click the Options button. Tick the Share Files And Folders Using SMB (Windows) box.

In the list of users below that box, put a tick next to the account you want to share. Enter the account’s password in the Authenticate dialog box and click OK. Repeat these steps for any other accounts you wish to share, and click Done.

By default, OS X will share the Public folders for each user you just enabled. You can select other folders to share if you like: Click the plus-sign (+) button under the Shared Folders list and select the folder or drive you want to share.

You can define access permissions for each shared folder in the Users section. If you’re the only user who will be sharing files between systems, you should already be on the list, with Read & Write privileges already selected.

If you have multiple users on your network and you aren’t picky about who has access to your Mac’s files, select Everyone from the Users list and set permissions (Read & Write, Read Only, or Write Only [Dropbox]). To control access user by user, click the plus-sign (+) button at the bottom of the Users section and either select each person from your Address Book or click the New Person button and enter a name and password there.

The Mac folders you’ve just shared should now be available from your Windows PC.

Windows XP  Click the Start menu and select My Network Places. If you don’t see the Mac listed under Local Network, click the Folders icon in the toolbar. In the Folders column on the left, look for the Mac under My Network Places. (It may be under Entire Network/Microsoft Windows Network/Workgroup.) Double-click the Mac entry and enter the username and password for the account you want to access.

Windows 7  Click the Start menu and select Computer (or go to any Windows Explorer window.) In the sidebar, click the disclosure triangle next to Network. You should see your Mac’s name there. Click on it, and the shared folders will appear in the pane on the right.

After you enable file sharing on the Windows PC; it will show up as another shared volume in the Mac's Finder; you can specify which of its folders are available.

Share a PC’s files
The process of setting up a Windows PC to share its files with a Mac varies depending on which version of Windows you’re using.

Windows XP  If you haven’t set up file sharing before, open the Start menu and select My Network Places. Click Set Up A Home Or Small Office Network in the left column. When the Network Setup Wizard appears, click through the screens until you get to the one for File Sharing And Printing. Select Turn On File And Printer Sharing, and click Next. Windows will then ask you to restart the PC to implement your changes.

By default, the Shared Documents folder is available to other users on the network. To share another folder, right-click it in any Windows Explorer window and select Properties from the shortcut menu. Open the Share tab and select the options you want.