How to reclaim HDD space from local Time Machine backups on Apple laptops

I do all of my development work on a laptop, more specifically on a MacBook Pro. Recently, I went through a ‘Spring Cleaning’ of past projects, old photos, and other files that I need to keep but don’t need to have taking up space on my laptop.

I spent some time moving files to external hard disk drives (HDDs), which helped with the problem somewhat, but then it dawned on me when looking at the OS X System Information panel, that more than 80 Gigabytes (that’s almost a third of one of my laptop’s partitions!) was filled with “Backups.”

After some research, I discovered that Time Machine (Apple’s excellent backup application) stores what it calls “Local Snapshots” to the HDD, in an effort to make sure backups are available even when the laptop is not connected to an HDD designated for Time Machine backups.

Having local backups is nice for traveling, or working away from where your Time Machine volume is housed; but since my laptop is usually hooked up to my Time Machine volume, and I backup all the important stuff in the cloud, I didn’t need all of this space filled up with partially redundant backups.

It is true that Time Machine manages the space that Local Snapshots takes up (read more about how it works on Apple’s Support site, but I wanted to free up all the space immediately. After some research and tinkering, I was able to work out a surefire way to release all the HDD space held hostage my Local Snapshots.

How to reclaim the HDD space from Local Snapshots

First, a quick overview on what we’re going to do: we’re going to tell Time Machine we don’t want Local Snapshots to be made anymore; then we’ll restart your computer, during which Time Machine will release all of the HDD space taken up by the Local Snapshots it thinks we don’t want anymore; then (if you’d like to, and I recommend that you do) we’ll turn Local Snapshots back on, and make an initial Snapshot to set us back on our merry way.

A few things to note first:

- Local Snapshots are only created on laptops running OS X that have Time Machine enabled; if you don’t have Time Machine enabled and/or you are using a desktop computer with OS X, you don’t have to worry about Local Snapshots taking up HDD space

- In order to perform all the necessary steps, you will need to be logged into an account on the laptop that has Administrative privileges

- You will also need to know your Administrative Password

- And lastly, you will need to have access to the Terminal application (it's not as scary as it sounds, trust me)

- Step One: Opening the Terminal

Open the Terminal application. The easiest way to find it is to do a Spotlight search (click on the magnifying glass icon near the top right corner of your screen) with the word “Terminal”.

- Step Two: Disabling Local Snapshots

Type the following command into Terminal (be careful to match the spelling and spacing *exactly*) and press 'return’.

sudo tmutil disablelocal

Note: You may get a warning about the 'sudo’ command, and that data may be lost; so long as you enter the above command *exactly* as written you should be fine.

- Step Three: Enter Your Administrator Password

Enter your Administrator Password and press 'return’. Your password may not appear as you are typing; this is normal.

- Step Four: Restart your computer

Quit the Terminal application and then restart your computer. (It is necessary to restart your computer for the HDD space taken up by Local Snapshots to be released properly)

- Step Five: No seriously, restart your computer

Welcome back! (I’m assuming you restarted your computer, if you didn’t, please do so before continuing)

The following steps are optional, but highly recommended.

- Step Six: Reenabling Time Machine’s Local Snapshots

Now that the space taken up by Local Snapshots is available to be used as you see fit, it may seem an odd recommendation to reenable the feature. I recommend doing so in order to allow Time Machine to work as intended by Apple, and so you aren’t ever in a situation where you can lose work; because losing work is always a bad thing.

Reopen the Terminal (as in Step One) and enter the following command to reenable Local Snapshots:

sudo tmutil enablelocal

- Step Seven: Enter Your Administrator Password (again)

For security reasons, anytime you use the 'sudo’ command, you are required to enter your Administrator Password.

- Step Eight: Make a new Local Snapshot

To start Time Machine off on the right foot again, I recommend manually creating the first Local Snapshot. You do this by entering the following command in the Terminal (notice you do not use the 'sudo’ command this time):

tmutil snapshot

And you’re done! Feel free to quit the Terminal application at any time, and go about using your computer as normal.

You shouldn’t have to worry about doing 'Spring Cleaning’ on Time Machine’s Local Snapshots for quite a while, but it’s good to check in from time to time to see how much HDD space they are taking up.

You can easily see how much space is being used for Local Snapshots by going to the Apple menu, selecting “About this Mac”, clicking on the “More Info…” button, and then clicking on the “Storage” tab. The part of the bar graph labeled “Backups” is the amount of space taken up by Local Backups.

Remember, Time Machine does manage this space automatically, but it may not be as aggressive about it as you may like; which is why I created this tutorial. You shouldn’t need to manually clear out the Local Snapshots on a regular basis. I recommend only doing so if you are getting short on HDD space and can’t delete or move any other files off your laptop; otherwise, I’d leave Time Machine to work its magic, eventually saving the day when that file goes missing or somehow gets deleted accidentally.

Happy Time Machining!

Sources
“About Time Machine local snapshots”
“Terminal 101: Checking on Local Backups in Time Machine”
“Free disk space by removing TimeMachine local snapshots”