Time Machine creates incremental backups of files that can be restored at a later date.[1] It allows the user to restore the whole system or specific files from the Recovery HD or the macOS Install DVD. It works within Mail, iWork, iLife, and several other compatible programs, making it possible to restore individual objects (e.g. emails, photos, contacts, calendar events) without leaving the application. According to an Apple support statement:

�Time Machine is a backup utility, not an archival utility, it is not intended as offline storage. Time Machine captures the most recent state of your data on your disk. As snapshots age, they are prioritized progressively lower compared to your more recent ones.��[2]

For backups to a network drive, Time Machine allows the user to back up Mac computers over the network, and supports backing up to certain network attached storage devices or servers, depending on the version of Time Machine. Earlier versions worked with a wide variety of NAS servers, but later versions require the server to support a recent version of Apple's Apple Filing Protocol (AFP), and Time Machine no longer works with servers using earlier versions of the Server Message Block (SMB) protocol[3] typical for Windows servers. Some of the legacy support can be re-enabled by using hand-tuned configuration options, accessed through the Terminal. Apple's Time Capsule acts as a network storage device specifically for Time Machine backups, allowing both wired and wireless backups to the Time Capsule's internal hard drive. Time Machine may also be used with any external or internal volume.

Time Machine saves hourly backups for the past 24 hours, daily backups for the past month, and weekly backups for everything older than a month until the volume runs out of space. At that point, Time Machine deletes the oldest weekly backup.