Mac Startup disk almost full? Here is how to free up some space

Apple Mac lineup has been around for years and ranks among the best laptops you can buy on the market. One of the best things when it comes to Apple Mac series lies in its stability and great battery life. In July 2018, Apple announced a refresh to its MacBook Pro lineup following months of rumors and speculation. With the 2018 MacBook Pro, Apple retains the best aspects of the previous models while adding eighth-gen ‘Coffee Lake’ Intel processors under the hood.

Apple MacBook does not tend to slow down over time thanks to its optimized hardware and software. However, it has its own issues that may ruin your experience. In reality, a lot of Mac owners claim that they get a warning message that says “Your startup disk is almost full”. This means that you need to make some room on your startup disk before it runs out. Full startup disk problem is pretty common among the Mac community as it pops up every year. And, the best shot to deal with it is to delete files you no longer use to reclaim some storage space. And that is what this article is all about. However, before proceeding, there are a couple of things you need to understand about Mac startup disk.

In this guide, we have made a list of the best tips for clearing some space on your Mac. We recommend you update your Mac before moving ahead. Keep in mind that a new macOS software update usually comes with performance enhancements and bug fixes, so it’s a good idea to stay-up-date.

  1. First, what is a startup disk?

By default, your Mac boots up from its built-in disk, but you can change your startup disk on your Mac as long as it contains macOS operating system. The coolest part is that your startup disk could be an external storage device out there. A startup disk that is running out on space can impact negatively Mac’s performance.


If you have recently noticed that your Mac is slowing down, then there is a good chance that your startup disk is almost full. Fortunately, there are a number of tips for dealing with a startup disk that’s running out on storage. If you have multiple disks with your Mac, then you need to identify which one is your startup disk. To do this, click on the Apple menu at the top, then select System Preferences and click on Startup Disk. Once you are in, you should see a list of all your hard disks. To find out which one is your startup, select About this Mac from the Apple menu and then check out the macOS version number.

  1. Back up your Mac

Before proceeding with the tips on how to clear space, make sure you back up your Mac. In reality, backing up is a smart thing to do if you want to protect your data in case of file corruption. In macOS, Apple is making things much easier than before, mainly thanks to a built-in tool called Time Machine.


Time Machine has been part of macOS for years, serving as a perfect, convenient tool for backing up your files, photos, or videos. To enable Time Machine backups on your Mac, click on Apple menu at the top, then select System Preferences from the pull-down menu and choose Time Machine. After that, click Select Backup Disk, select which disk you wish to store your Time Machine backup and check the box next to Back Up Automatically.


  1. Optimized Storage

In macOS High Sierra, Apple added Optimized Storage to its operating system. Basically, Optimized Storage serves as a perfect tool for saving storage space on your Mac. Once enabled, it automatically moves your files into the Cloud. If your startup is almost full, you will get the option to optimize storage. Click on Manage and then click on Optimize. Besides, you can empty trash automatically on your Mac. To do this, you simply need to click on Turn on in the Empty Trash Automatically section and hit Turn on again to confirm your action.


If you change your mind, then you can turn off Optimize Storage on your Mac. To do this, click on the Apple icon at the top left corner of the screen, then select System Preferences and click on iCloud. After that, click on Options, then uncheck the box for Optimize Mac Storage at the bottom and hit Done.

  1. CleanMyMac X

If you are looking for a third-party app that offers an advanced cleanup tool, then CleanMyMac X should be your choice. CleanMyMac X is one of the best apps for Mac that helps control your Mac system and clean up the mess. The app offers a beautiful user interface with separate sections for Cleanup and Protection. With CleanMyMac X, you can remove all the files you no longer need on your Mac. Basically, the app scans the entire operating system to check for viruses, malicious files, or junk files, and then remove them. CleanMyMac X now costs $39 per year, which is cheaper than its competitors on the market.

These are the best tips for dealing with the full startup disk problem. Hopefully, this works best for you. If you have got any questions, let us know in the comments below.

Was this article helpful?
Categories Mac
About John Smith

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.