How File Backups Work

Backup And Restore provides graphical tools for manually initiating backup and restore sessions and for scheduling automatic backups. All client computers that store important data should have automatic backup scheduled. For more information, read the section titled "Best Practices for Computer Backups" later in this tutorial.

After you first configure automatic file backup using Backup And Restore, Windows 7 will regularly back up all files. The first time a backup is performed, a full backup is done, including all important user documents. Subsequent backups are incremental, backing up only changed files. Older backups are discarded when the disk begins to run out of space.

For example, if you configure a nightly scheduled backup and change a file every day, a copy of that file will be stored in each day's Backup Files folder (described in "File and Folder Backup Structure" later in this tutorial). By storing multiple versions of a single file, Windows 7 gives users the opportunity to choose from several older copies of a file when using the Previous Versions tool (also described later in this tutorial). When you restore files, you only need to restore from a single backup because Windows 7 automatically locates the most recent version of each file. In previous versions of Windows, you need to first restore from the last full backup and then restore any updates from incremental or differential backups.

Windows 7 uses Shadow Copy to back up the last saved version of a file. Therefore, if a file is open during the backup (such as the storage file for local e-mail or an open document), the file will be backed up. However, any changes the user makes since last saving the file are not backed up.

Only administrators can configure scheduled backups or manually initiate a backup. However, once configured, scheduled backups do not require a user to provide administrative credentials. Restoring files does not require administrative privileges unless a user attempts to restore another user's file.

If you perform a file backup to a shared folder, the credentials used to run the backup must have Full Control share and NTFS permissions for the destination folder (known as Coowner permissions in the Windows 7 Setup Wizard). To reduce security risks, set up a user account to be used only by the backup application, and configure share and NTFS permissions to grant access only to the backup user. The backup account requires administrative privileges to the computer being backed up, but it needs permissions only to the share and folder on the target computer.