Maintenance procedure · Written to ASD-STE100 Issue 9 · Formatted to ANSI Z535
Set Up a Time Machine Backup on a Mac
macOS Ventura 13 and later — choose an external disk, set Time Machine up in System Settings, and prove the backup can actually give a file back
ApplicabilityAny Mac running macOS Ventura 13 or later, backing up to an external USB or Thunderbolt disk connected directly to the Mac. Checked against Apple's documentation on 2026-07-29, when the current Mac User Guide was published for macOS Tahoe 26 and Apple's Time Machine support article carried a published date of 6 July 2026. The network destinations Apple also supports — a shared Mac, a NAS device, an AirPort Time Capsule — are named here but not instructed.
Task timeat least 20 min to 1 hr 9 min (40 of 41 steps estimated) editorial estimate, not a measurement
PersonnelOne
Revisionv1 · 2026-07-29
BEFORE YOU BEGIN
Before you begin. This procedure is general reference information, not professional advice. Equipment varies by manufacturer, model, and year. Always follow the documentation supplied with your equipment — where it differs from this page, follow the manufacturer. Verify that you have the tools, the working conditions, and the ability to do this task safely. If anything is unclear, if the equipment is damaged, or if the task exceeds your experience, stop and use a qualified professional. You are responsible for your own safety and for the outcome. This site accepts no liability for any loss, damage, or injury arising from the use of this information.
Specifications marked unverified could not be traced to a manufacturer source. Do not rely on them — obtain the value from your equipment documentation.
Summary
Time Machine is the backup built into every Mac, and it is one of the few pieces of software that is genuinely finished: you plug in an external drive, answer two or three questions, and it keeps hourly, daily and weekly copies of your files from then on. The part people skip is the last part. A backup nobody has ever restored from is a hope, not a backup, so this page ends by walking you through pulling one real file back out of it.
It is written against Apple's own documentation as it stood on 29 July 2026, for macOS Ventura 13 and later, which is where Time Machine moved into System Settings. Two things this page will not do: it will not tell you which drive to buy, and it will not invent a way to recover a lost encryption password, because Apple does not document one. It does tell you the disk size Apple asks for, what Time Machine leaves out of the backup, and the exact point where the answer stops being ours and starts being Apple Support's. Every step traces to an Apple support article or a Mac User Guide topic, and both are linked in the sources.
Safety
NOTICE
READ THE macOS VERSION ON YOUR MAC FIRST. Menu names change with a macOS update. This page follows the Apple documentation for macOS Ventura 13 and later.
NOTICE
A TIME MACHINE BACKUP IS NOT A FULL COPY OF macOS. Time Machine does not copy the system files or the apps from the macOS installation. For a full recovery, you must install macOS again first.
Necessary equipment
Item
Note
Mac computer
The steps apply to macOS Ventura 13 and later.
External disk
Use this disk only for the Time Machine backups.
USB-C cable or Thunderbolt cable
The cable must fit a port on your Mac.
Pen and paper
Make a record of the macOS version and the backup password.
Find the macOS version
Estimated 2 min
NOTEApple moved the Time Machine controls from System Preferences to System Settings at macOS Ventura 13. The menu names on an earlier macOS are different.
Select the Apple menu at the corner of the screen.
CONSULT THE DISK MANUFACTURER AND THE APPLE DOCUMENTATION IN THE SOURCES
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
NOTICE
COPY THE FILES THAT YOU MUST KEEP TO A DIFFERENT DISK BEFORE YOU START. The setup can erase the external disk. An erase removes all the files on that disk permanently.
Examine the external disk for files that you must keep.
The setup can ask you to erase the disk.
An erase removes all the files on the disk permanently.
MAKE A RECORD OF THE BACKUP PASSWORD BEFORE YOU CONTINUE. Apple gives no method to recover a lost backup password. Without that password you cannot restore a file from an encrypted backup.
For protection of the backup from other persons, set Encrypt Backup to on.
An encrypted backup needs a password at each restore.
Your Mac can ask for the password when you connect the disk or when you start the Mac.
This page uses one term for each item and holds it throughout, as ASD-STE100 requires. Equipment sellers and other guides use the names below for the same parts.
Time Machine
Also called: mac backup, apple backup, time machine backup, macbook backup, the backup thing on a mac
backup disk
Also called: backup drive, external hard drive, external hard disk, time machine drive, backup hard drive, usb drive, portable drive
System Settings
Also called: system preferences, mac settings, settings app, preferences, control panel on a mac
APFS
Also called: apple file system, mac format, disk format, apfs encrypted
local snapshot
Also called: snapshot, time machine snapshot, local backup, backup without the drive plugged in
Encrypt Backup
Also called: encrypted backup, backup password, time machine password, password protect my backup, encrypt time machine
restore
Also called: recover, get my files back, undelete, roll back a file, recover a deleted file on mac
When to use a professional
Stop if your Mac cannot find the backup disk after the setup. Read the Apple topic about Time Machine problems in the sources. Then speak to Apple Support.
Stop if a backup fails or stops before the end more than one time. A repeated failure can come from the disk hardware. Speak to Apple Support or to the disk manufacturer. Give them the macOS name and the macOS version from the first section.
Stop if you cannot remember the password for an encrypted backup. Apple gives no method to recover that password. Make a new backup on a different disk. Then speak to Apple Support about the old disk.
Stop if the internal disk of your Mac has a fault. A restore of your files cannot repair a damaged macOS installation. Speak to Apple Support.
This page does not give the steps for a backup to a network. A shared Mac, a NAS device and an AirPort Time Capsule are each different. The instructions for a NAS device come from the NAS manufacturer.
Common questions
How big does my Time Machine drive need to be?
Apple's answer is at least twice the storage capacity of your Mac, and its own worked example is a 1TB Mac wanting a 2TB backup disk. That is a floor, not a target: Time Machine keeps old versions of files as well as current ones, so the more history you want the more room it needs. Apple also says the Mac will tell you when Time Machine needs more space, which is the honest version of this answer — you find out in use. We are not going to name a drive model, because that number depends on your Mac and on how much you keep, and a page that guesses it is guessing with your files.
Can I use the same drive for backups and for my other files?
Apple says to use the Time Machine backup disk only for Time Machine backups. There is a documented exception for advanced users: add a second APFS volume to the same physical drive and use one volume for Time Machine and the other for storage. Apple's caveat is that the Time Machine volume should still be twice the storage capacity of your Mac, and the two volumes share the drive's space. If you simply drop files onto the backup disk instead, Apple is explicit that Time Machine will not back those files up and the space left for backups shrinks.
Should I turn on Encrypt Backup?
It depends on what happens if the drive is lost or stolen, and only you know that. What matters more is the part people find out too late: Apple documents no way to recover a lost backup password, and you must supply it to restore anything from an encrypted backup. So the real question is not whether to encrypt, it is whether you have somewhere reliable to keep the password — a password manager, or paper somewhere safe. If you do not, an unencrypted backup you can actually restore from beats an encrypted one you cannot. Apple also notes you may be asked for the password when you connect the disk or restart the Mac, not only when restoring.
Does Time Machine back up everything, so I could rebuild my whole Mac from it?
Not by itself, and this is the most common misunderstanding about it. Apple states that Time Machine excludes system files and the apps installed as part of macOS. If the system is damaged, Apple's documented route is to reinstall macOS first and then use Migration Assistant to bring your information back from the Time Machine backup. So the backup does hold your files, your settings and your third-party apps, but it is not a bootable clone and it is not a one-click rebuild.
What are local snapshots, and do they mean I don't need a drive?
No. Time Machine also saves local snapshots on the same disk as your original files, which lets you recover an earlier version of a file even when the backup drive is not attached. Apple says those snapshots are created hourly, are only made on disks using APFS, and are kept for up to 24 hours or until the disk needs the space. That makes them useful for the file you broke this morning and useless for the disk that failed this afternoon, because they live on the disk that failed. Apple's own recommendation is still to back up to somewhere other than your internal disk.
Can I back up to a network drive or a NAS instead of plugging a drive in?
Apple supports it, and this page deliberately does not instruct it. Time Machine can back up to another Mac shared as a backup destination, or to a third-party NAS that supports Time Machine over SMB, and Apple's guidance is to prefer SMB where you get the choice. Two things are moving, though: Apple says backups to NAS devices over AFP are not recommended and will not be supported in macOS 27 or later, and that the shared-Mac route is only recommended when both machines are on macOS 11 or later. NAS setup instructions come from the NAS manufacturer, not from us and not from Apple.
How often does Time Machine actually back up?
By default, hourly backups for the past 24 hours, daily backups for the past month, and weekly backups for every month before that. When the disk fills, the oldest backups are deleted to make room, which is normal behaviour rather than a fault. You can change the interval in Time Machine settings under Options, using the Backup Frequency menu, and that menu includes a manual setting if you would rather back up only when you say so. On a Mac laptop there is a separate switch for backing up on battery power.
My Mac shows System Preferences, not System Settings. What now?
You are on macOS Monterey 12 or earlier, and the steps on this page will not match your screen. Apple renamed System Preferences to System Settings in macOS Ventura 13 and moved Time Machine under General, which is the layout this page follows. Time Machine itself works on the older releases; the route to it is just different, and Apple's support article has a separate section for the setup steps in your version of macOS. Read your version from the Apple menu, then About This Mac, before you follow anything.
Every specification on this page is traced to one of these sources. Tier 1 is a manufacturer document, a published standard, or a government safety authority. See Standards for the full tiering rule.
Current version 1 · updated 2026-07-29 · next review due 2027-07-29
v1 · 2026-07-29First draft. Built entirely from Apple's own documentation, opened by direct HTTPS fetch on 2026-07-29: the support article 'Back up your Mac with Time Machine' (Apple published date 6 July 2026), 'Backup disks you can use with Time Machine' (published 7 July 2026), and the Mac User Guide topics 'Back up your files with Time Machine on Mac', 'Choose a backup disk and set encryption options on Mac', 'Types of disks you can use with Time Machine on Mac', 'Exclude files from a Time Machine backup on Mac', 'Restore items backed up with Time Machine on Mac', 'Start, pause, or resume a Time Machine backup on Mac', 'Time Machine settings on Mac', 'About the Time Machine backup password on Mac' and 'Time Machine troubleshooting on Mac'. The guide identified itself as the Mac User Guide for macOS Tahoe on that date. Five Mac User Guide URLs in wide circulation return HTTP 200 while redirecting to the guide index, which means the status code looks healthy and the cited content is not served; those are recorded under rejected in data/sources-additions-set-up-macos-time-machine.json with their live replacements. The procedure was verified against Apple's documentation, not executed on a Mac, and this record says so rather than claiming a test result. Where Apple documents a network destination — a shared Mac, a NAS device, an AirPort Time Capsule — this page names it and does not instruct it, because the NAS half of those instructions belongs to the NAS manufacturer. The four verified specifications carry spec_key null: this record was drafted concurrently with others and the drafting session was not permitted to write data/specs.json, so the registry entries must be added when the record is merged. Each value traces to the Apple source named on it.
Corrections to this page are listed in the public corrections log. Reports that are credible and not yet verified are listed in the public errata register, and an open one renders above the step it concerns.
Comments and corrections
Found an error? A correction with a manufacturer source is applied and logged publicly. You can also write to corrections@fixchecklist.com.
Every step above carries its own report control, which tags the report with that step so a correction reaches the right place. For anything about the procedure as a whole — the order of the sections, a step that is missing, something that did not match your equipment — use this: report something about this whole procedure.
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