FIX: Your startup disk is almost full

When a Mac’s startup disk begins to lack free disk space and starts to fill up, it displays a message stating, “Your startup disk is almost full” to the user. The startup disk on a Mac refers to the partition of the Mac’s HDD or SSD where the Operating System is located. This signifies that when the partition of your Mac, which contains the version of OS X you use, begins to fill up, you’ll begin seeing this message from your computer. Contrary to most of the other messages that Macs display to users, this is not an error and doesn’t imply that a problem or issue exists. Rather, this message is simply a warning that informs the user their startup disk is filling up. Consequently, if they do not heed the warning and clear up space on it, they may start experiencing problems such as jitters and lag.”

This warning message essentially serves as a 911 call from your computer to you, implying that your computer needs your assistance. The process of eradicating the “Your startup disk is almost full” alert is fairly straightforward – you merely need to create space on your startup disk by removing unnecessary data. Once done, the message will disappear. Regardless of the season, your computer requires you to embark on a spring cleaning spree to return it to its intended state – the speedy and lightning-fast computer you know and love.

Before proceeding with the steps to clear and free up space, you should know how to check the available space. This will allow you to monitor the amount of space you have managed to free up throughout these steps.

To check the storage, open Finder.


Locate your Macintosh HD under Devices in the left pane. Press CTRL + CLICK on it, and choose ‘Get Info’.

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The two fields you need to examine are ‘Capacity’ and ‘Available’. ‘Capacity’ indicates how much it can store, and ‘Available’ shows how much is currently free. When you clear up and delete files, the ‘Available’ space should increase.

The following are the steps you should go through in order to free up space on your Mac’s startup disk and get rid of this warning message:

Step 1: Empty your Mac’s Trash.

When you delete a file or folder from your Mac, it doesn’t entirely disappear. Instead, it’s simply moved to the Trash, as long as it doesn’t occupy a massively large portion of disk space. To begin freeing up space on your startup disk, the first step you should take is to empty your Mac’s Trash. Everything in the Trash essentially occupies space on your Mac’s startup disk.

Hold CTRL, and while doing so, click on Trash in your Dock. Click on Empty Trash. Click on Empty Trash once again to confirm the action.


Mac users need to remember that iPhoto has its own independent Trash. Therefore, once you have emptied your Mac’s main Trash, remember to head over to iPhoto and empty its Trash as well. Bear in mind this step, because after deleting files from other locations, you will need to continue emptying the trash.

Step 2: Clean out your Downloads folder

The amount of junk that your Downloads folder can accumulate may astonish you. Once you have cleared out the Trash, the next step you need to take is clean out your Downloads folder. Delete any and all files and folders that you no longer need or don’t recognize, and organize what is left of the Downloads folder once you are done.


Step 3: Tidy up your Movies folder

The Movies folder on a Mac is where all of your videos (including those movies and television shows you love to watch so much) are located. Any video, be it a movie or an episode of a television show, can take up a significantly large amount of space. Since that is the case, you need to access the Movies folder and get rid of all the video files you no longer need and won’t be watching any time soon. Getting rid of unnecessary data from the Movies folder can make a huge difference in the amount of free disk space your Mac’s startup disk has.

Step 4: Get rid of music that you no longer listen to

Next, visit your Music folder. Delete all the unnecessary audio files, especially duplicates, to enhance your Mac’s performance.

Step 5: Compress as many files and folders as you possibly can.

If, while cleaning up your Mac, you come across a file or folder that you don’t use very frequently but can’t bear to part ways with, there is a solution – simply compress it. Compressing a file or folder shrinks the amount of disk space that it occupies while at the same time making sure that you can easily access it whenever you want to. To compress a file or folder on your Mac:

Press Ctrl, then, while holding it, click on the file or folder you wish to compress. Choose ‘Compress’ and select your preferences, such as choosing the type of compressed file (like .zip) you want to convert the file or folder into. Confirm the action.


Step 6: Clean up your Desktop,

Cleaning up your Desktop can not only increase the amount of free disk space your startup disk has but can also help your Mac run a tad bit faster. Simply delete anything on your Desktop that you no longer need and organize the rest of the stuff on your Desktop.

Step 7: Uninstall applications you no longer need

Go to your Applications folder and uninstall any applications that you no longer need or use. Ensure to uninstall them in the proper manner, as simply dragging their folders to the Trash can result in parts and pieces being left behind. See the steps here.

Step 8: Delete old backups of your iTunes library,

Over time, your Mac can accumulate a large amount of backups from your iTunes library, all of which can take up quite a bit of disk space. You can get rid of the older iTunes library backups and consequently free up disk space on your startup disk. To do so, simply:

Open Finder.

Click on Go in the menu bar at the top left corner of the window.

Click on ‘Go to folder…’.

Navigate to ~/Music/iTunes/Previous iTunes Libraries.

Peruse all the backups and delete almost all of them, leaving behind only the three to five most recent backups.


Step 9: Erase old iOS backups

Old backups of iOS can take up a lot of disk space, which is why it would be wise for you to remove them. To do so, simply:

Open Finder.

Click on Go in the menu bar at the top.

Click on ‘Go to folder…’.

Navigate to ~/Library/Application Support/MobileSync/Backup/.

Remove almost all of the backups, leaving behind only the three to five most recent ones.

Step 10: Delete cache files.

When you open an application for the first time, your Mac creates cache files for the application so that it launches faster the next time you open it. Over time, your Mac can accumulate a lot of cache files which can take up a lot of disk space. Removing these cache files, hence, can free up a lot of space on your startup disk.

Please open Finder.

Click on ‘Go’ in the menu bar at the top.

Click on ‘Go to folder…’.

Go to ~/Library/Caches.

Delete the files and folders that take up the most space.

Click on ‘Go to folder…’.

Navigate to /Library/Caches.

Delete the files and folders that take up the most space.


Kevin Arrows

Kevin Arrows is a highly experienced and knowledgeable technology specialist with over a decade of industry experience. He holds a Microsoft Certified Technology Specialist (MCTS) certification and has a deep passion for staying up-to-date on the latest tech developments. Kevin has written extensively on a wide range of tech-related topics, showcasing his expertise and knowledge in areas such as software development, cybersecurity, and cloud computing. His contributions to the tech field have been widely recognized and respected by his peers, and he is highly regarded for his ability to explain complex technical concepts in a clear and concise manner.
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