Tech 101: Everything you need to know to verify Time Machine backups (2023)

Tech 101: Everything you need to know to verify Time Machine backups (1)You're trying to use Time Machine to keep up-to-date backups of your Mac data, but there's a nagging concern in the back of your mind. How do you know that the backups are good?

That's a good question we should all ask about our backups. There are several ways to make sureTime Machine backups are in good condition, and we will cover most of them in this guide.

Before we move on to verifying the integrity of your backups, there is an important distinction in Time Machine technology that you should be aware of. a line in the sand, if you will. Time Machine backups created on OS X Yosemite and earlier have more limited backup testing capabilities than those created on OS X El Capitan and later. We have included notes on which version of the Mac operating system the verification method works on. Let's start with that.

Check Time Machine hard drive
Before we try to verify the files in a Time Machine backup, you need to make sure that the Time Machine hard drive has no problems. Begin withturn off the time machineand then use Disk Utility First Aid to check if your Time MachineThe disc is in good condition.🇧🇷 If errors are found, use the "Repair Disk" option in Disk Utility as described in the link above. (Need dedicated Time Machine storage?these external solutionsto find the perfect drive for your Mac).

The eyeball method of checking the time machine
This somewhat simplified way of checking the status of your backups is done by using Time Machine to restore one or two files and then checking (looking at) the files to see if they appear to be intact. Before you complain that this method doesn't sound very reliable, you're absolutely right, but it does provide a quick and easy way to verify that the basics of Time Machine and your backups actually work.

The eyeball method works for any version of Time Machine or Mac OS. The only requirement is that you have a Time Machine backup on your Mac:

Access Time Machine by choosing "Enter Time Machine" from the Time Machine menu or by launching the Time Machine application located in the /Applications folder.

Use the arrow in the Time Machine window to go back to an earlier time.

In the Time Machine Finder window, right-click a file and select Restore "File Name" to... from the pop-up menu.

The time machine shuts down.

After a moment, you'll be presented with a standard Finder picker, where you can choose a location to save your Time Machine file. Navigate to the location where you want to save the file and click New Folder. We strongly recommend creating a new recovery folder, as there is a bug in some versions of Time Machine that causes all files that occupy the same folder as the selected file to also be recovered. Restoring to a new folder isolates the file when the error occurs.

The file is restored to the new folder location.

Open the recovered file and examine it to make sure it is in the correct format. This can be as simple as viewing the contents of a document, previewing a recovered image, or checking the file size and creation date.

If the file or files look fine and no disk errors are detected when you run Disk First Aid, you can be sure that your Time Machine backups are healthy.

To use:If you've run into any errors while using Disk First Aid, it might be time to investigate.spare discs🇧🇷 Unlike other storage media we use, we recommend not tolerating drive failures when backing up.

Check backups on Time Machine drives
Backup verification has been a built-in feature in Time Machine since 2009, when the first Time Capsule was released. Make sure your backups work for all versions of Time Machine and Mac OS since Snow Leopard.

But before you say "Yippie! Easy way to verify my backups!", the Verify Backups feature only works for Time Capsules, NAS (Network Attached Storage) that supports Time Machine, or attached external hard drives to a Mac on your network It can be deployed on the local network and running on your own Mac. If the Time Machine backup location meets any of the above criteria, you can run the verification function as follows:

Make sure Time Machine is available as a menu bar item. If not, open the Time Machine preferences window and select Show Time Machine on the menu bar.

Hold down the Option key and click the Time Machine menu bar item.

You should see the Verify backups option. If the option is grayed out, the Time Machine hard drive does not meet the requirement of being a Time Capsule, NAS, or remotely mounted external hard drive.

Select the Verify backups item.

Time Machine starts the verification function. You can observe the status of the verification process by opening the Time Machine settings window; a status bar shows the progress. If an error is discovered, Time Machine will notify you; Otherwise, no information will be provided, following the old adage that no news is good news.

Compare backups as tmutil
The following method to verify a Time Machine backup can be used instead of the backup verification method we just saw. It works for any type of Time Machine backup, not just Time Capsule or NAS, and it works for any version of Time Machine or Mac OS.

Unlike verifying backups, the diff function is performed byTerminal, with the tmutil command. It provides a file-by-file comparison of the last backup to your Time Machine disk with the current state of your Mac. As such, it would be very rare for the diff function to produce a 100% match, since there are almost always files on your Mac that update in the background.

Launch Terminal in /Applications/Utilities.

At the terminal prompt, type:

sudo tmutil compare -s

The -s option forces tmutil to only compare file sizes. You can have the diff function check for many additional file parameters, but since the diff is done on a file-by-file basis, it can take a long time; The file size limit helps save time and still get reasonable results. Still, the compare command can take anywhere from 20 minutes to a few hours, depending on the size of your backups.

The results are presented in the following formats:

🇧🇷 (file size) / path to file: The exclamation point (!) indicates a difference in file size between the backup and the archive on your Mac.

+ (file size) /path to file: The plus sign (+) indicates a new file that does not exist in the backup.

– (file size) /path to file: Specifies a file that was removed from your Mac but still exists in your backup.

The problem with the compare command is that it is time sensitive. As the time between the backup point and the current point increases, more and more files will be different. So while Compare can serve as a pointer when used directly after a backup, it quickly becomes less useful over time.

Verify checksums (OS X El Capitan and later)
Starting with OS X El Capitan, Apple added a method to verify files in the Time Machine backup, by comparing the checksums created by Time Machine when the files were backed up with a checksum derived from the actual files in the Time Machine backup. backup.

This is a file-by-file comparison, so the process may take a while. The tmutil function only generates errors and warnings when a problem occurs. If the backups match the stored checksums, the command simply exits with no results.

The command has the form:

sudo tmutil verifychecksums /path to the backup drive. For example, if I want to check my Time Machine drive, which is called Tardis, the command is:

sudo tmutilcheckchecksums/Volumes/Tardis

If you're not sure of the path to the backup drive, enter the first part of the command (sudo tmutil verifychecksums) and drag the drive from Time Machine into the Terminal app. The actual path to the drive is entered automatically.

To use: If you use the drag technique to enter the path, it will probably add an extra space at the end of the path. Be sure to remove the extra space before running the command. Otherwise, you may receive error messages about route enumeration errors.

Tech 101: Everything you need to know to verify Time Machine backups (5)

Start Terminal, if it's not already open, and type the following at the Terminal prompt:

sudo tmutil verifychecksums /path to the backup drive

Be sure to replace /path to the backup drive with the actual path to the Time Machine backup.

Run the command by pressing Enter or Enter.

To use:If the Time Machine backup you are verifying was originally created with OS X Yosemite or earlier, the verify checksums option in tmutil will not work, even if you are verifying in a newer version of Mac OS, and will simply return an error.

The checksum option in tmutil returns it to the terminal prompt if there are no errors and essentially provides no confirmation text of any kind. On the other hand, if there are problems, Terminal prints messages indicating the type of errors found.

When should Time Machine backups be verified?
You probably don't need to check your backups every time Time Machine runs. However, it might be a good idea to review Time Machine when you first set up your backup system, change backup drives, or make other changes to your Mac or backup system. Of course, if you've never reviewed your backups before, now is a good time to give it a try.

Related article:Yes, you can use one drive for Time Machine and file storage

More themes you may like:

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the authortom nelson


Tom has been an avid Mac user since Mac Plus. He is also known to dabble in the dark side, aka Windows, and has a well-deserved reputation for being able to explain just about anything to anyone. Tom's experience includes more than 30 years as an engineer, programmer, network administrator, software tester, software reviewer, database designer, and designer of computer networks and systems. His online experience includes working as a system operator, forum leader, author, and software library manager.

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What does verifying a Time Machine backup do? ›

If you back up to a network disk, Time Machine periodically verifies that your backups are in good condition. This scheduled verification happens automatically, but you can manually verify a backup at any time. On your Mac, click the Time Machine icon in the menu bar.

How do I know when my Time Machine backup is complete? ›

First, add the Time Machine icon to the menu bar, if you haven't already. Head to System Preferences > Time Machine, then check the option at the bottom of the window. Next, click the Time Machine icon in the menu bar. Then, hold down the Option key, and a “Verify Backups” option will appear.

How do I get Time Machine to recognize old backups? ›

Open Time Machine settings and reselect your backup disk. If you erased your backup disk and began having trouble, reselecting it may fix the problem. If you're using a Time Capsule as your backup disk, use AirPort Utility to make sure it's set up properly and connected to your network.

Why is my Mac Time Machine not backing up? ›

General troubleshooting

Make sure your backup disk is plugged in, turned on, and securely connected to your Mac. If your backup disk is on a network, make sure both the disk and your Mac are connected to the network. If the network is experiencing problems, your backup disk may not be available.

What are the three 3 factors to consider for successful backups? ›

For backup strategies to be successful the process has to successfully execute in three areas; backup, recovery, and time.

How should backups be verified? ›

How to Verify Backups—4 Ways
  1. Manual Check/Access the Backup Files. Many cloud backup applications allow a user to view the contents of a backup, like it was another disk. ...
  2. Run a Backup Verification Application. ...
  3. Health Check. ...
  4. Perform a 'Test Restore.
Mar 11, 2020

Does Apple Time Machine restore everything? ›

If you made a Time Machine backup of your Mac, Migration Assistant can use that backup to restore your personal files, including apps and everything in your user account. If you prefer to restore just a few files or earlier versions of those files, learn how to use Time Machine to restore specific files.

How do I know when Seagate backup is complete? ›

There are two ways to verify the backup completed:
  1. Looking within the Seagate Dashboard software.
  2. Browsing the folder structure for the data.

Is Time Machine the best way to backup a Mac? ›

A Time Machine backup makes it especially easy to transfer all your data, settings, and apps from one Mac to another. It's also really intuitive to use.

How far back does Apple Time Machine go? ›

Once the first backup is complete, Time Machine checks your Mac for new, changed, and deleted files once every hour. Time Machine keeps these hourly backups for the past 24 hours, then keeps a daily backup for the past month.

How far back does Mac Time Machine go? ›

Use Time Machine to back up your Mac

Once Time Machine is set up, it will create and store one backup every hour for the past 24 hours, daily backups for the past month and one backup a week for all previous months until it runs out of space.

Does Apple Time Machine delete old backups? ›

Generally, Time Machine automatically deletes old backups. Once your storage device is running low on space, macOS deletes anything unnecessary, such as your oldest Time Machine backups. However, if you need to delete your backup manually, here's what to do.

How do I force a Time Machine backup on a Mac? ›

On your Mac, click the Time Machine icon in the menu bar, then do any of the following:
  1. Start a backup: Choose Back Up Now.
  2. Pause a backup: Choose Stop This Backup.
  3. Resume a backup: Choose Back Up Now.

How do I restore my entire Mac from Time Machine? ›

How to Restore macOS with Time Machine
  1. Make sure your Time Machine backup disk is connected to your computer.
  2. Restart your Mac.
  3. While the system is turning on, hold down the Command + R keys. ...
  4. Release the keys when you see the Apple logo on your screen. ...
  5. Then select Restore from Time Machine backup, and click Continue.

How do I do a full Time Machine backup on my Mac? ›

How to enable Time Machine backups on your Mac
  1. Select System Preferences from the Apple menu.
  2. Choose the Time Machine icon. …
  3. Click Select Backup Disk.
  4. Select which disk you'd like to use as a Time Machine backup. …
  5. Check the Back Up Automatically box in order to automatically back up your Mac to your chosen disks.

What is the 321 rule for backup? ›

You may have heard of the 3-2-1 backup strategy. It means having at least three copies of your data, two local (on-site) but on different media (read: devices), and at least one copy off-site. We'll use “socialsecurity.

What is the 321 rule? ›

The 3-2-1 Rule, as I like to explain it, states the following: There should be 3 copies of data. On 2 different media. With 1 copy being off-site.

What is the 3-2-1 0 backup rule? ›

Here's what the 3-2-1 backup rule involves: 3: Create one primary backup and two copies of your data. 2: Save your backups to two different types of media. 1: Keep at least one backup file offsite.

What is the 3 2 1 rule of backups Why is this important? ›

The 3-2-1 backup strategy simply states that you should have 3 copies of your data (your production data and 2 backup copies) on two different media (disk and tape) with one copy off-site for disaster recovery.

Should you test your backups? ›

Testing Data Backups

The importance of testing backups lets you verify the necessary data is available for recovery. Plus, testing helps you learn how to actually implement recovery following a data loss. If a backup test fails, you can take the steps needed to ensure you don't actually lose valuable information.

What every IT auditor should know about backup and recovery? ›

The team should include all of the functions and roles necessary to quickly and completely restore computer operations. There should be a document that identifies all of the members of the teams, their respective roles and the steps each would take in restoring operations.

How many Time Machine backups should I keep? ›

You should always have the most recent 24 hourly snapshots and the last rolling month's worth of daily snapshots. Time Machine retains weekly snapshots older than a month until it has to delete them.

Does Apple Time Machine save photos? ›

Use Time Machine: After you set up Time Machine, it automatically backs up the files on your Mac. If you ever lose the files in your Photos library, you can restore them from the Time Machine backup.

Does Time Machine backup all profiles on a Mac? ›

Time Machine runs at the system level and backs up all users, as dialabrain indicated.

What is the lifespan of a Seagate hard drive? ›

It is common to see MTBF ratings between 300,000 to 1,200,000 hours for hard disk drive mechanisms, which might lead one to conclude that the specification promises between 30 and 120 years of continuous operation.

How long should a Time Machine backup take? ›

Your external backup drive is now ready, and a Time Machine backup will start within 2 minutes. It's that easy. If Time Machine has been previously set up, open Time Machine and choose Select Disk then select the external drive.

How often do Seagate hard drives fail? ›

What does this all mean for hard drive storage in 2021 overall? Overall, failure rates were low, with an average AFR of 1.01% across all drives, although smaller drives (those below 12TB) made up the majority of issues.

Why is it important to test the backup? ›

The importance of testing backups lets you verify the necessary data is available for recovery. Plus, testing helps you learn how to actually implement recovery following a data loss. If a backup test fails, you can take the steps needed to ensure you don't actually lose valuable information.

What is verify backup integrity? ›

Backup integrity check process

The Backup Integrity Check is meant for ensuring the integrity of backup data in two stages: the backup data check and index structure check.

How long should a Time Machine backup take Mac? ›

Wondering how long the Time Machine backup will take? This can vary widely. It's likely that if you've only made a few changes since the last backup this one won't take very long: just a few minutes. But if you haven't backed up for a while, or if this is your first backup, it's probably going to take some time.

Why is it important to backup and verify company files regularly? ›

The Importance of Backups

Making backups of collected data is critically important in data management. Backups protect against human errors, hardware failure, virus attacks, power failure, and natural disasters. Backups can help save time and money if these failures occur.

What are the 3 types of backups? ›

The most common backup types are a full backup, incremental backup and differential backup. Other backup types include synthetic full backups and mirroring.

What is the first and most important step needed in point in time backups? ›

Typically, the first step in creating a backup strategy—especially an enterprise backup strategy—is to determine recovery time objectives and recovery point objectives for each data source and application.

What is the most efficient way to verify the integrity of database backups? ›

RESTORE – The most effective way to validate that your backups are good is to run a test Restore. If your Restore is successful, you have a solid backup. Make sure to run a test restore on your Full, Differential, Point in Time, and Transaction Logs!

What are three characteristics of a secure backup? ›

Backups should be physically protected as well as encrypted, password protected, and restricted as to the ability to recover and restore to alternate locations.

How can you ensure the integrity of your backups? ›

Ensure integrity and accessibility when making backups of data
  1. Have contact information available for the person responsible for the data.
  2. Ensure that those who need access to backups have proper access.
  3. Communicate what data is being backed up.


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