Set Up Time Machine for Backup

Client Notes

Last week, I helped Leslie erase and recycle her old Mac, coached Deborah in some Mac basics, and supported Margie in preparing to backup data and upgrade macOS. I also enabled Janis to consolidate two Dropbox accounts into one, saving a bundle of $$.

How Does Time Machine Work?

By default, Time Machine backup routines run hourly. This works well for users who create and edit a lot of documents and may want to restore old versions.

In macOS 13 and later, you can choose to have backups run daily or weekly, which may be beneficial for other use cases. Or, using TimeMachineEditor, which I mentioned in I Got Caught, you can create other custom schedules.

With each Time Machine backup, the software creates a timestamped entry on your external drive and does the following:

1. Copies new files created since the last backup
2. Copies the latest versions of files changed since the last backup
3. Archives older versions of files changed since the last backup
4. Archives files deleted since the last backup
5. Deletes the oldest backups as needed to recover space on the backup drive

Time Machine is also very efficient with space and avoids creating duplicate files. Instead, it uses an array of “hard links” and other database features that point to identical copies of files and folders that already exist on an older backup. You can read more in this Eclectic Light article.

Select a Destination

To prepare to set up Time Machine, connect an external drive that you want to use as a backup destination. Apple recommends choosing a drive whose capacity is at least twice that of your startup disk. I recommend one that is at least twice that of the volume of data you think you will have over the next five years.

You can find some product recommendations on my website. As of this publication, I’m currently pointing clients toward Samsung T7 and Crucial X9 SSDs, commonly available in 1TB, 2TB, and 4TB sizes for $65–230. Feel free to reach out for a recommendation based on your needs.

Your Mac will erase the drive and set it up for use with Time Machine. So, if your drive already has data on it, make sure you have another copy or don’t care about it anymore.

Set Up Time Machine

When you’re ready, open System Settings > General > Time Machine (or, in macOS 12 and earlier, System Preferences > Time Machine). Click a relevant button such as Add Backup Disk, Select Disk, or + and proceed with the drive you connected.

When available, select Encrypt Backups and enter a password in the first two fields. I recommend using your computer password. You’re required to specify a password hint, so I usually enter “mac.”

Next, Time Machine will confirm that you want to erase the drive. This may confuse you if you connected a brand new drive that you thought was already empty. However, to be used for this purpose, the drive must be formatted in a particular way. That’s the underlying meaning of this step.

After the drive is ready, Time Machine will begin the first backup. After a short while, it will provide an estimate of remaining time. Since your Mac assesses its entire backup routine before starting, this statistic is usually reliable.

Depending on the speeds of source and destination, the amount of data, and the performance of the Mac, I’ve seen the initial backup take anywhere from 1 hour to 24 hours.

Next Steps & Considerations

If you selected to encrypt the backup, it’s a good idea to eject the drive in the Finder, disconnect from the computer, and reconnect. The first time the drive mounts, the Mac will ask for its password.

I recommend first selecting to remember the password on your keychain and then entering the password. This way, you won’t have to enter the password every future time you connect the drive.

There are a number of methods to eject a drive:

1. Make a Finder window, look for the drive name in the Locations section of the sidebar, and click its eject button (⏏)
2. In the Finder, choose Go > Computer and eject the drive from that list
3. If the volume appears on the Desktop, drag its icon to the Trash, which will change to an eject icon

You may recognize the eject icon from that of a VCR or DVD player, or a key in the top right on many late Apple keyboards.

Going forward, you may choose whether to leave your Time Machine drive connected all the time. When the drive is available, the utility will run as often as you have specified.

Your decision may be based on the Mac being a desktop or laptop (and therefore stationary or mobile), the average speed of the backup operation, and/or how much ambient noise is produced. Backups to SSDs tend to be fast and quiet whereas other drives may be louder and/or take longer.

You may also choose to use multiple backup drives and run them in alternation, perhaps keeping one offsite for security purposes. I’m happy to consult with you on your particular scenario and help strategize the best approach.

Finally, I recommend keeping the Time Machine status menu in the menu bar for easy ways to manually initiate a backup, check the status of an active backup, or restore data. In macOS 13 and later, go to System Settings > Control Center and set Time Machine to Show in Menu Bar. In macOS 12 and earlier, go to System Preferences > Time Machine and check Show Time Machine in menu bar.