Time Machine is a powerful piece of software. Did you know that it will take local backups of your disk. This means that if you have an external hard drive, which is not plugged in your still get a backup. This means it will backup files onto your own hard drive for a period of time. This will continue to happen until you disk becomes 80% full. This can explain why disk space may seem to disappear or become full even if you don’t seem to do anything. This post will tell you a little bit more about these backups, there size and location; as well as how to delete them.
View Local Backups
You can view the size of these local backups. The quickest way to do this is go to the Apple Icon within the tool bar and select About This Mac. From the little menu that pops open select More Info. Then select the storage tab. You will be given an overview of files. One of the options will be ‘Backups’ these are your time machine backups.
This is a lot of space to take up. Time Machine looks to be smart enough to pick the largest hard drive.
You can see the physical location of files using Finder. From the menu bar select Go > Go To Folder and enter /Volumes/MobileBackups a finder window will open.
Each folder is a backup. It is built in a special way which allows it to store only files that have changed, but yet keep a complete copy of everything. I wouldn’t recommend you change anything.
Disable Local Backups
If these backups are beginning to take up too much space they should be self limiting and reduce in size as you disk space shrinks. However, if you have an SSD which are limited on space, or have your Time Machine drive always plugged in, you may want to disable them.
To do this open Terminal within Applications > Utilities. Then type the following:
sudo tmutil disablelocal
You will get no confirmation, however the order will be executed. You will need to enter your admin password.
The existing snap shots will be deleted. This make take a while however.
To turn the command back on enter the following:
sudo tmutil enablelocal
You will need to enter you password again. Note that if you have a desktop Mac such as an iMac you will need to use this command twice.
Create A Local Backup
If you want to create a new local backup you can. Within Terminal enter the following into the command prompt and hit enter.
There will be no response, however in the background a new local backup will be created of any files that have changed. You can verify if by viewing the physical files and looking at the timestamp.
Local snapshots is something that your Mac has built right in. I didn’t realise it till a few days ago (its actually says it if you read the text within Time Machine in System Preferences). These are useful in there own right.
They do take up a bit of space and if you want this space back you can be disabling the command. Note that your Mac can turn this back on so you may want to check every couple of months if you are really tight on space.