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There‘s nothing more frustrating than your Mac grinding to a halt and getting the dreaded "your startup disk is almost full" error message. When your Mac‘s built-in storage fills up, performance suffers and you may not even be able to boot up your computer. But don‘t panic! There are several ways you can reclaim space on your startup disk and get your MacBook running smoothly again.
In this guide, I‘ll explain what the startup disk is, show you how to check your disk usage, and provide 6 proven methods to free up storage space. I‘ll also share some tips to prevent your Mac‘s drive from filling up again in the future. If you follow these steps, you can fix your full startup disk issue quickly and easily without being a tech expert.
What is the Mac Startup Disk and Why Does It Fill Up?
The startup disk is the built-in hard drive or solid-state drive where macOS, your applications, and your personal files are stored. Everything on your Mac lives on this disk.
Over time, as you accumulate more files, install more programs, and generate more caches and logs, your startup disk can start to fill up, especially if you have a MacBook with limited built-in storage capacity. Even regular macOS updates take up extra space.
When your disk approaches maximum capacity, you‘ll see the "your disk is almost full" alert and your Mac may feel sluggish and unresponsive. In extreme cases, you may not be able to save files or even start up your computer.
How to Check Your MacBook Startup Disk Space
The first step is to check how much free space is left on your startup disk:
- Click the Apple menu icon and select "About This Mac."
- In the window that appears, click the "Storage" tab.
- Look at the bar at the top for "Macintosh HD" (or the name of your startup disk). This shows how much space is used and how much is still available.
You can also click the "Manage" button to see a breakdown of what‘s taking up the most space. Pay attention to the categories using the most storage, as these are good targets when you want to free up space.
Now that you know where you stand, let‘s look at ways you can reclaim some of that precious disk space.
6 Ways to Free Up Space on a Full Startup Disk
Luckily, there are a number of strategies you can use to clear space on your startup disk and get your Mac running smoothly again. Here are 6 of the most effective:
1. Store Files in iCloud or on an External Drive
One of the best ways to free up local storage is to move large files like photos, videos and backups to iCloud or an external drive. iCloud comes with 5 GB of free space, and you can cheaply upgrade to get more. Pricing varies by country, but in the US it‘s just $0.99/month for 50 GB of storage. To enable iCloud:
- Click the Apple menu icon and open "System Settings…"
- Select your Apple ID in the sidebar, then click "iCloud."
- Next to "iCloud Drive", click "Options."
- Check the box for "Desktop & Documents Folders" to store those files in iCloud.
You can also manually move files to iCloud, iCloud Drive, or an external hard drive or SSD via the Finder. Consider archiving old projects, moving large media collections off your startup disk, and storing only current documents locally.
2. Empty the Trash and Downloads Folders
When you delete files, they go to the Trash, but they aren‘t fully deleted until you empty the Trash. To permanently delete trashed files and reclaim that space:
- Click and hold the Trash icon in the Dock.
- Select "Empty Trash."
I recommend enabling the option to automatically delete files that have been in the Trash for more than 30 days. Just open "Finder Preferences", select "Advanced", then check the box next to "Remove items from the Trash after 30 days."
Also get in the habit of cleaning out your Downloads folder regularly. Those downloaded ZIP files, installers, and email attachments can really add up.
3. Uninstall Unused Applications
Old applications, especially large ones like games, can consume substantial disk space. Removing apps you no longer use is an easy way to recover significant storage:
- Open a Finder window and go to the Applications folder.
- If you see any apps you don‘t need anymore, drag them to the Trash.
- Empty the Trash to fully delete them.
Many applications also leave behind preferences, saved states, and caches after you delete them. To thoroughly remove all traces of an app, I recommend using a dedicated uninstaller tool like AppCleaner. It finds all the files associated with an application so you can delete them in one fell swoop.
4. Clear System and Browser Caches
Caches store frequently accessed data to help your Mac run faster, but over time they can balloon in size. Clearing out old and unneeded caches can free up gigabytes of disk space. Here‘s how:
- Open a Finder window.
- Press Command+Shift+G to open the "Go to Folder" dialog.
- Type in ~/Library/Caches and hit Enter.
- Delete the files/folders in this directory. (But don‘t delete the folders themselves or your applications won‘t be able to cache data again.)
In addition to system caches, web browsers like Safari, Chrome and Firefox cache lots of data. Periodically clearing the browser cache will recover disk space and protect your privacy.
I find it‘s much easier to manage caches and other hard-to-reach files with a dedicated cleaning utility like CleanMyMac X. It has a "System Junk" module that scans for unnecessary cache files, logs, broken preferences, and other space hogs and lets you delete them safely with one click.
5. Delete Old Time Machine Backups
If you use Time Machine to back up your Mac, the backups can pile up and occupy a lot of disk space on your startup drive or backup disk. To free up that space, you should delete old backups you no longer need. Here‘s how:
- Open "System Settings…" from the Apple menu.
- Click "Time Machine" in the sidebar.
- Click "Options…" next to the backup disk.
- Click the "Delete All Backups" button.
Note that this will remove all your backups from that disk, so make sure you have a fresh backup first. You can also manually delete individual backups by control-clicking a backup in the Time Machine interface and selecting "Delete Backup."
6. Restart Your MacBook
If your Mac still says the startup disk is full after trying the above steps, a simple restart may help. Restarting clears some temporary files and gives macOS a chance to perform routine maintenance and cleanup. Just click the Apple menu icon and select "Restart."
Tips to Keep Your Startup Disk From Filling Up Again
Freeing up space on your disk is only half the battle. You also want to prevent it from filling up again too quickly in the future. Here are some tips:
- Regularly check your disk usage and clean out junk files. Set a reminder to do this at least once a month.
- Be mindful about what you install. Only keep applications you actually use. Avoid bloated programs.
- Move large, infrequently accessed files to an external disk or the cloud. Consider using a cloud storage service like Dropbox or Google Drive for your biggest files.
- Control what is stored in your Desktop and Documents folders since those can quickly get out of hand, especially if you have iCloud syncing enabled.
- Empty the Trash and clear out your Downloads folder frequently.
- Keep on top of software updates. Updates often include more efficient codebases and space-saving features.
- Invest in an external drive or additional cloud storage so you can offload more files from your local disk.
- If your MacBook has an SD card slot, use it! A high-capacity SD card is an affordable way to add more local storage.
What If Your Startup Disk is Still Full?
If you‘ve diligently followed the steps above and your MacBook is still low on space, it may be time to consider upgrading your storage. This is especially true if you have an older Mac with a traditional hard disk drive (HDD). Replacing the HDD with a larger solid-state drive (SSD) can give you more breathing room and significantly boost performance at the same time.
Upgrading the built-in storage on modern MacBooks is very difficult though, as most components are soldered directly to the logic board. Consider using an external drive for additional storage instead.
If your MacBook is more than 5-7 years old, it may be time to think about upgrading to a newer model with a bigger drive. The cost may be more than offset by the productivity boost you‘ll get from a faster machine.
The Bottom Line
Running out of space on your MacBook‘s startup disk is annoying, but fixing it is within your reach, even if you aren‘t a tech guru. The key is knowing where to look for the biggest space hogs and proactively clearing out files you no longer need.
Remember, you can recover the most space by moving large media files to an external drive or the cloud, emptying the Trash and Downloads folders, deleting unused applications, clearing caches, and removing old backups. Integrating these habits into your regular computer maintenance routine will help keep your Mac happy, healthy, and speedy.
If you‘ve tried everything and you still can‘t get enough free space, consider upgrading your Mac‘s storage or investing in an external drive for your bigger files. And make sure you have a good backup system in place in case something goes wrong!
Do you have any other tips for freeing up disk space on a Mac? Or a story about fixing a jam-packed drive? Let me know in the comments.