Note: This is an updated version of an article from 2018.
With macOS, Apple makes it easy to set up a drive to be a target for other Macs to use with Time Machine.
Say you have a Mac mini on your network, and a MacBook Pro. You can hook up an external drive to that Mac mini, and within a few minutes, be backing your MacBook Pro up across your network using Time Machine.
Here’s how to do it.
1. Prepare Time Machine Drive
Once your drive is plugged in, open Disk Utility and format it as APFS. For this article, the drive I set up is named “Remote TM.”
2. Share the Drive Using System Preferences
Once the drive is ready, navigate to the General section in System Settings, then navigate to the “Sharing” sub-section and turn it on with the slider.
Then click on the small i button in the “File Sharing” section:
This will open a new pane. On this new pane, click the + button below the list of “Shared Folders:”
This will open a standard file picker window. Use it to navigate to the drive you have set up for remote Time Machine, then click “Add:”
Once you do, you will be returned to the previous screen, but this time, your Time Machine drive will be listed:
3. Set Up Drive as a Time Machine Destination
From the File Sharing pane pictured above, right-click on the drive in question and select “Advanced Options” from the menu:
Doing so will open another new pane, that will let you tell macOS that the drive should be shared as a Time Machine backup destination. Select that option, and if desired, set a backup size limitation. This can be helpful if more than one user will be using this drive for Time Machine.
Once you are done with this, save the changes and exit System Settings.
4. Add Folder as Time Machine Destination
Now go to a computer that will be using this drive for Time Machine. Navigate to the “Time Machine” section of the “General” pane in System Settings and select “Add Backup Disk…”
This Mac should automatically see your drive, assuming the two Macs are on the same network. Here, you can see my “Remote TM” drive as hosted on my Mac mini, which I named “Castle:”
Clicking “Set up Disk…” will prompt you to log in to the remote computer with the user account on that machine:
After being authorized, System Settings will present the standard Time Machine set up user interface. If you wish to encrypt your backup, set your password and click “Done.” If you do not want to encrypt your backup, toggle the slider off:
5. Back, Back, Back It Up
You are now ready to backup one Mac to another on your local network. Be warned that this can be slower than having a drive hooked up directly to a machine, but it’s very handy for laptops that don’t have a permanent home on a desk.
