My iPhone 14 1TB can no longer back up to my Mac mini M2 because "not enough free space is available on this Mac"

Batlo wrote:

Why can’t I use an external drive to back up my phone?

1) Because iPhone backups need to be kept on the Mac's internal drive.

see "Back up iPhone using your Mac" at > Back up iPhone - Apple Support

2) Running your Mac low on free space is also asking for serious trouble including data loss.

see "Move or delete files to free up storage space" at > Free up storage space on Mac - Apple Support

What you need to do is free up a large chunk of storage space on your Mac mini's 256GB internal storage drive.

One way to do that, is to move your larger Photos, Music or Movie Libraries to an external drive.

> Move your Photos library to save space on your Mac - Apple Support

> Change where your music files are stored on Mac - Apple Support

> Move your iMovie for Mac library - Apple Support

There was a time (in the iTunes area) where you could select where your iPhone backup went. I have mine on a external SSD:

However, I've not found a way to do it via the Finder in the newer systems.

However, a quick AI search on the subject got me this:

"You can change your iPhone backup location by using a symbolic link (symlink) to point the default backup folder to a new location, such as an external drive. This involves moving the existing MobileSync backup folder to your desired location, deleting the original folder, and then creating a new symlink in its place that redirects the system to the new folder. 

Step 1: Find the current backup folder

1. 1. Connect your iPhone to your Mac.
   2. Open Finder.
   3. Click on your iPhone in the Finder sidebar.
   4. Click the General tab, then click Manage Backups to see the current location of your backups.
   5. To manually locate the folder, open a new Finder window, select Go > Go to Folder, and type ~/Library/Application Support/MobileSync/Backup/. This path will show you the current backup folder. 

Step 2: Relocate the backup folder 

1. 1. Open a Finder window and navigate to ~/Library/Application Support/MobileSync/. This folder contains the Backup folder.
   2. Copy the entire Backup folder to your new location (e.g., an external SSD).
   3. Once the copy is complete, delete the original Backup folder from the ~/Library/Application Support/MobileSync/ directory to free up space. 

Step 3: Create the symbolic link 

1. 1. Open the Terminal application.
   2. Use the ln -s command. Drag the new Backup folder you moved in Step 2 directly into the Terminal window. This will automatically populate the path.
   3. After the path to the new folder, type the path to the original MobileSyncfolder, which is ~/Library/Application Support/MobileSync/. The full command should look something like this: ln -s /Volumes/YourExternalDrive/Backup ~/Library/Application\ Support/MobileSync/.
   4. Press Enter. This creates a symbolic link in the original location that points to the new folder. 

Step 4: Verify the new backup location 

1. 1. In Finder, go back to ~/Library/Application Support/MobileSync/. You should now see a new Backup folder with an arrow icon, indicating it's a symbolic link.
   2. Back up your iPhone again from the Finder or Apple Devices app to ensure it now saves to the new location.
   3. You can also check the space on your new drive to confirm it is filling up. Note that the system may still check the main drive for free space before starting a backup."

You might give it a try as it just might work. Be sure to backup the iPhone before you try it and then make a Time Machine backup of your boot drive. That will give you the tools to recover the current backup via Time Machine if the above doesn't work.

Batlo wrote:

iPhone 14 1TB storage. 2023 Mac mini M2 256GB storage. Trying to back up my phone I now get the message "not enough free space is available on this Mac". What is the official work around for this problem?

The iPhone 14 only came with 128GB, 256GB or 512GB so you must be talking about an iPhone 14 Pro or Max.

Regardless, with only 256GB storage in your Mac mini and considering the space taken by macOS, your applications and a modicum of user data, there's hardly enough space to back up even a 128GB iPhone.

AFAIK the only viable "workaround" would be to install macOS on an external drive that is large enough (in your case I'd suggest a 2TB external drive) ... then boot from the external drive and back up your iPhone there.

Do yourself a favour and follow Martin's advice . . . get a 2TB SSD, install macOS on it and boot your mini from it.

I have been doing that for over 2 years on both my minis . . . one advantage is that it leaves your internal SSD untouched as all the wear takes place on the cheap external.

I would advise using a 2TB NVMe in a USB-C housing . . . this setup can be purchased from Amazon for £100 upwards.

You could use a Thunderbolt housing (£60 or more extra) which will be faster but you will never notice the difference in everyday use . . . except copying massive (100GB) files will be quicker . . . in every other way your Mac will be just as fast.

Backing up a 1TB device to a 256GB device will be problematic at best. Reduced thee size of the data ion your phone or backup to a larger computer. Or, use iCloud to backup.

Back up to iCloud instead.

You need to free up considerable space on your boot drive. The method I used is the following:

1 - get an external SSD, formatted APFS. An excellent candidate is this external SSD from OWC (MacSales.com): 1.0 TB OWC Envoy USB 3.2 (10Gb/s) Bus-Powered Portable NVMe SSD as it's only $120. OWC is considered by many to be the premier hardware supplier for Macs.

2 - copy the Pictures, Music and Movies folders to the external SSD and rename the folders to Pictures-2, Music-2 and Movies-2.

3 - verify the Photos, Music and Movie libraries work as expected on the external SSD.

4 - once verified delete the contents of the Pictures, Music and Movies folders. Do not delete the folders them selves.

5 - in the Finder ➙ Sidebar settings pane uncheck Pictures, Movies and Music.

6 - drag the Pictures-2, Music-2 and Movies-2 folders into a Finder window sidebar.

This will free up a lot of space (one should try to maintain 80-100 GB of free space to facilitate optimal system and application performance) and allow you to backup your iPhone to your Mac.