iPhone back ups aren’t small. They aren’t the same size as the total used space on an iPhone but they can still take up GBs of space on your Windows drive. Out of the box, you cannot change where the back up is saved to. You can move the back up to a different place, and move it back when you need to restore from it but that is a very clunky way to do it. If you’re not averse to using junction links though, you can back up your iPhone to an external drive using iTunes.
Back up location
There are two versions of iTunes available at present; a desktop app version, and a UWP app version. The back up location for both apps differs slightly. You need to know where the app is currently saving the back up to in order to create a junction link that points it elsewhere.
C:\Users\Your User Name\AppData\Roaming\Apple Computer\MobileSync\Backup
UWP app version
C:\Users\Your User Name\Apple\MobileSync\Backup
New back up location
Connect the drive that you want to back up your iPhone to. Not only does this work for external drives, it can also be used for internal drives. At the root of the drive, create a folder called ‘MobileSync’.
Next, cut the Backup folder from your windows drive, and paste it inside this newly created MobileSync folder. Make sure you cut and paste it, instead of copying it.
Create junction link
If you have iTunes open, close it. Open Command Prompt with admin rights. You need to execute the command below however, you have to change it to match the path to your current back up folder, and the new one you just created.
Run the command below for the UWP iTunes app;
MkLink /J “C:\Users\Your User Name\Apple\MobileSync\Backup” “E:\MobileSync\Backup”
Run the command below for the desktop iTunes app;
MkLink /J “C:\Users\Your User Name\AppData\Roaming\Apple Computer\MobileSync\Backup” “E:\MobileSync\Backup”
In both cases, you want to replace ‘Your User Name’ with your actual user name. You can change the drive letter to which ever letter is assigned to the drive you want to take the back ups on.
What’s going on?
You might wonder why you can use this method to back up your iPhone to an external drive but not change the back up location via iTunes. This is because as far as iTunes is concerned, it is still backing up your iPhone to the original location that it picked out. The junction link is what’s rerouting the files to a different drive and different location.