Make Space On Macbook Air Startup Disk

To make more space on your startup disk you will need to: Delete files from your Mac. Move files to an external hard drive or cloud storage. Or install a second internal hard drive on your Mac. So, now that we know what a startup disk is, we need to talk about how to fix it.

1. Macbook Startup Disk Missing
2. Macbook Air Startup Disk Download

• By far the easiest way to clean your Mac hard drive is with CleanMyMac, get the free trial download here: You can.
• A newer software version is available: CleanMyMac X. Download CleanMyMac X free edition here A step-by-step guide to make the 'Startup.

A full startup disk is something that every Mac user will experience. This problem used to be known as 'Startup disk full' notification. However, on newer macOS versions this message has been changed to 'Your disk is almost full.'

But luckily, it's a problem that has many solutions. And in this article, we'll go over:

• What is startup disk full?
• What's causing 'Your disk is almost full' alert?
• How to fix startup disk full?
• How to prevent 'Your disk is almost full' problem?

However, we also understand that some people are short on time and just want to fix startup disk full. So, if you're not really interested in what it is and why it happens, just skip the next two sections and head to 'How to Clean Your Startup Disk'.

Or, even better, if you're looking how to clear space on Mac, we'd highly recommend a utility called CleanMyMac X. It'll help you clean up gigabytes of disk space in just minutes (you can download it here).

Note: if you're running macOS Sierra (or higher), it has a built-in option of Optimized Storage that is supposed to solve the problem of the full hard drive by moving files into the cloud.

By clicking 'Manage' you can open the menu and see what Optimized storage offers. However, it moves junk and useless files to the cloud together with your files, and eventually, you end up paying for iCloud storage to store junk. So we still recommend getting CleanMyMac and actually dealing with extra files rather than simply moving them.

Now, with all that said, let's get into what exactly 'Your disk is almost full' means.

Understanding What 'Your Disk is Almost Full' Means

What is a startup disk?

A startup disk, as taken from Apple Support article, is a volume or partition of a drive that contains a usable operating system. Still confused? Let's break it down for you.

Your Mac hard drive consists of disks (or partitions). Each disk (or partition) has your Mac data on it, which consists of your operating system, applications, etc. Most Mac users have just one disk but power users may have two or more.

Let's look at an example of a Mac with only one hard disk:

• Your Mac's hard drive is 500GB.
• It has one 'disk' on it, so all 500GB of storage is on that disk.
• The disk has an operating system (OS X El Capitan), and user data (apps, etc).
• And since you only have one disk, this is your startup disk: all 500GB.

A Mac with two disks will have the storage divided between them. The Mac drive with the OS on it is the startup disk while the other drive is just used for storage of files. It's possible to have multiple startup disks, but most Macs will only have one.

Why your disk is almost full?

This is easy. It's a lot like why is your fridge full? There is no more space! Your disk is almost full and this is very bad news for any drive. A hard disk should never get beyond 85% capacity (especially a startup disk) as you will experience slowness and errors the further you get above that mark.

If your startup disk is full and you get a message of warning from your Mac, this is a serious indication that you need to clear up storage immediately.

What to do when your disk is almost full?

So how do you fix your almost full startup disk? The same way you solve the problem of a packed fridge - you need to clear up storage, of course. To make more space on your startup disk you will need to:

1. Delete files from your Mac.
2. Move files to an external hard drive or cloud storage.
3. Or install a second internal hard drive on your Mac.

So, now that we know what a startup disk is, we need to talk about how to fix it. Let's take a closer look at your disk space to see exactly what is causing your disk to be almost full.

What's Causing 'Your Disk Is Almost Full' Alert?

Short version: Take a look under-the-hood of your Mac.

Before we can see what is taking up space on your startup disk, first we have to find it:

1. Hover on the Dock at the bottom of your screen and open Finder.
2. Click on 'Finder' in the menu bar at the top of your screen.
3. Then select 'Preferences…'
4. In the window that opens, checkmark the 'Hard disks' checkbox.

After selecting this box, your desktop should now show the hard disks on your mac, in the form of icon(s), like this:

These are disks on your Mac that you can 'startup', this is because they have operating systems on them. If there is more than one of these hard disk icons that show up on your desktop, it means you've got multiple hard disks on your Mac. If you only have one, skip the down to 'What is taking up all of my startup disk space?' section.

If you have more than one, continue with the next step:

Click on the Apple icon at the top left of your screen System Preferences > Startup Disk.
Here, again, you'll find your hard disk(s); they're probably named something like MainSSD or MainHD. It will also display 'OS' and the version number of that OS. If you have more than one OS drive, your startup disk should be the one with the latest version of macOS running on it, but we're going to make sure of that in the next step.

I only have one and it looks like this:

To make 100% sure that you know what drive is your startup disk, follow these steps:

1. Click on the Apple Icon in the menu at the top-left of your screen.
2. Select 'About This Mac.'
3. Under macOS, you'll find a version number. Mine is 10.15.1, like so:

See how my version number in the 'About This Mac' window matches the number in my Startup Disk section? Yep — That's my startup disk. Found yours? Good.

What is taking up all of my startup disk space?

Now that we've identified our startup disk, let's take a closer look at how to clear up space on Mac:

1. Click the Apple Icon in the menu at the top-left corner of your screen.
2. Choose 'About This Mac.'
3. Click Storage.
   Note: If you are running an older version of OS X you may have to first click 'More Info…' and then 'Storage'.

Take a look at my hard drive disk:

I've got 500GB of storage, and about 275GB of it is free.

So, how big is your hard disk? How much free space do you have (if any — *gulp*)? And what's taking up the most space? It is important to consider drive capacity and data storage needs for future storage plans — we're not just here to fix the problem, for now, we're going to make sure you never have this problem in the future as well.

Now that we have the knowledge, it's time to take action and fix your Mac's 'Startup Disk Full' problem.

Let's go over 11 things you can do to help fix 'your disk is almost full.' These should also give you other ideas as to how else to fix it — You know your Mac better than we do!

1. Clear system storage on Mac

System storage cleanup sounds like a serious undertaking. But, technically, it boils down to just one thing: having the courage to scrap the old files.

1. Search for large ZIP/RAR archives in Downloads
2. Open your Desktop (Command + F3) and delete screenshots
3. In Applications, sort your apps by size. Delete the largest ones
4. Get rid of system junk files with a free version of CleanMyMac X
5. Restart your Mac to free up RAM.

2. Clean up cache files on your Mac

Cache files are files that help your Mac run programs a bit more smoothly. Think of them like blueprints for a house: your Mac has the blueprints for how a program is supposed to load/run/look, so it loads it faster; without them, it'd be like building it from scratch. However, over time, these caches can start to take up some serious space. Periodically, removing them can help clear storage. And don't worry, your Mac will create fresh, new ones after you restart your Mac. To remove caches:

1. Open a Finder window and select Go in the menu bar.
2. Click on 'Go to Folder…'
3. Type in ~/Library/Caches
   Delete the files/folders that are taking up the most space.
4. Now click on 'Go to Folder…'
5. Type in /Library/Caches (simply lose the ~ symbol)
   And, again, delete the folders that take up the most space.

Deleting cache files is generally safe for your Mac. And once you delete them, the applications and processes you run on your Mac will generate fresh, new ones. But, when deleting, worry more about removing them based on size rather than just removing all of them.

Also, you can check the /System/Library/Caches folder as well, but it might be better not to touch this folder without knowing what the items are. A utility that correctly cleans up these files (and pretty much everything else on this list) is, you guessed it, CleanMyMac X. It cleans up even your system caches with just a few clicks.

Oh, and once you're done with this list, restart your Mac so it can create these new cache files.

1. Open a Finder window and select Go in the menu bar.
2. Click on 'Go to Folder…'
3. Type in ~/Library/Caches
   Delete the files/folders that are taking up the most space.
4. Now click on 'Go to Folder…'
5. Type in /Library/Caches (simply lose the ~ symbol)
   And, again, delete the folders that take up the most space.

Deleting cache files is generally safe for your Mac. And once you delete them, the applications and processes you run on your Mac will generate fresh, new ones. But, when deleting, worry more about removing them based on size rather than just removing all of them.

Also, you can check the /System/Library/Caches folder as well, but it might be better not to touch this folder without knowing what the items are. A utility that correctly cleans up these files (and pretty much everything else on this list) is, you guessed it, CleanMyMac X. It cleans up even your system caches with just a few clicks.

Oh, and once you're done with this list, restart your Mac so it can create these new cache files.

Read more: How to Clear Cache on a Mac?

3. Get rid of localization files

Localization files are also known as 'language packs.' Lots of apps come with other languages that you probably don't need. To clear up space on your Mac, delete the ones you don't need:

1. Open a Finder window.
2. Go to Applications.
3. Ctrl+click on an application.
4. Select 'Show Package Contents.'

From here, go to Contents > Resources and look for files ending in .lproj. These are the languages your app has just in case you want to use it in another language, like Spanish (es.lproj). Drag the ones you'll never use to the Trash.

Again, a safer alternative to this would be to use CleanMyMac X. It gets rid of all of them with a click. No digging through application folders, just a cleaner Mac.

Read more: How to Delete Language Files from macOS?

4. Delete duplicate files

Even if you have the most organized Mac on a planet, duplicates happen one way or another. It can be a file you've mistakenly downloaded twice or a mail attachment you've opened several times. Regardless of how they appeared, those files sit on your Mac and gobble up storage.

But finding and deleting them is a time-consuming process if you do it one by one. So here's what you can do to save up time:

1. Open the Finder app on your Mac
2. Move cursor over File and click New Smart Folder
3. Click the '+' button in the upper right corner and choose the type of files you want to see
4. Now sort them by name to quickly spot duplicates.

Remember to pay attention to the date of creation to make sure you keep the true original, not the copy.

While this is the best way to remove duplicates manually, it takes lots of your time and dedication. It'd be much easier to leave this to Gemini 2: The Duplicate Finder.

This app quickly scans your Mac for duplicate and similar files and allows you to delete them within minutes. It keeps your originals safe and helps you easily retrieve files deleted by accident.

5. Remove old iOS backups

Backups can tend to take up a lot of space. You can find and remove them by:

1. Launching a Finder window.
2. Clicking 'Go' in the menu bar.
3. Selecting 'Go to Folder…'
4. Then, type in ~/Library/Application Support/MobileSync/Backup/

Get rid of all the old, outdated backups your Mac has been storing for a bit more extra space.

6. Remove iOS software updates

You can find all the unnecessary data for your devices by:

1. Opening Finder.
2. Selecting 'Go' in the menu bar.
3. Clicking on 'Go to Folder…'
4. And entering for iPad ~/Library/iTunes/iPad Software Updates
   or entering for iPhone ~/Library/iTunes/iPhone Software Updates

Delete downloaded files for any of the devices that you are not using anymore, or ones which software just already updated. Remember that after any of your devices have been updated, you don't need those files.

Read more: How to Delete iOS Software Updates from Mac?
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7. Remove unnecessary applications

This isn't often overlooked, but definitely under-appreciated. Removing old, unused applications is a great way to get some extra space on your startup disk. Go through your applications folder and get rid of all the apps you rarely use. But make sure you remove them correctly, don't just drag them to the Trash. If you do, you'll leave behind tons of leftover parts and pieces, and we're trying to get back startup disk space — It'll kinda defeat the purpose, no?

This is another place we'd suggest using CleanMyMac X. To completely remove any application, just launch CleanMyMac X, click Uninstaller, select your application, and then click Uninstall. You won't have to search all over for development junk that's left behind when Trash'ing an application. It's incredibly easy and saves you tons of time.

8. Clean up your photo library

Photos, photos, photos. Talk about tons of space! First and foremost, select only what you can get rid of, like image copies and maybe some photos that were mistakenly taken. You know, ones of the ground or something?

Ok, once your own files are taken care of, it's time to get rid of the files your system created. In Photos for Mac, it's cache files. In iPhoto, it's service copies. Both are a pain to find, but here's how you can get rid of them.

Photos cache includes iCloud local copies (created when you view pics from your iCloud photo library on a Mac), Faces cache (generated when you use Faces), and other app-related caches. You'd be surprised how much all that takes up if you regularly use Photos. For OS versions prior to macOS Sierra, here's the path to locate the cache:

1. Open Finder and navigate to your Photos library (normally, it's in the Pictures folder).
2. Ctrl+click your Photos library, and select 'Show Package Contents.'
3. Open resources, and then modelresource.

You should now see a lot more folders in your Finder window. Photos cache sits in these folders, but the tricky thing is that it's really hard to say what is safe to remove and what isn't. Deleting the wrong file can compromise the performance of Photos, which is why we highly suggest you use CleanMyMac X to clear the cache and system junk. It only removes files that are safe to delete, never a critical file or important image.

You can download CleanMyMac X for free and see how it works, it's so much safer than cleaning up system junk manually.

9. Clean up your Downloads, Movies, and Music folders

Have a closer look at these three folders. You'd be surprised at how many downloads can accumulate when you aren't paying attention. Clean out anything you don't need (or don't know) and organize the rest. It'll take a load off your mind to know that there's nothing excess there.

The Movies folder can be a pain, not because you're searching through tons of files, but it can be difficult to choose what to delete. Personally, I never want to get rid of Top Gun. It's amazing. I watched it 3 times in a row last weekend. But alas, sometimes you need to make sacrifices for the health of your Mac. Though, what you can do with movies you want to keep is to archive them. So, archive what you wish to keep and remove the rest.

How to archive/compress a file

Archiving a file doesn't mean to store deeper into the abyss of your Mac — but to turn the file into something smaller, into a compressed file (like .zip or .tar). By archiving a file, you shave off some memory. Archiving is essential for things you want to keep on your Mac, but don't often use, and helps you clear up some space. And that's what this is all about right? We're essentially doing the hokey-pokey on your Mac. To archive a file, just:

1. Ctrl+click the file you want to compress (recommended for movie files).
2. Select, 'Compress .'

The last place to sweep through is the Music folder. Find and remove duplicate music files first, and then clean up all the songs you downloaded on a weird Sunday afternoon cleaning the house.

10. Clean your Desktop

'Clean my desktop… but why?' Because some people's desktops are hard to look at, that's why. Organize your desktop and get rid of the stuff you just don't need on there. It looks better and helps your Mac act a bit faster (I don't know the rocket science behind this one, but it feels too good to be false). Your Mac doesn't waste time loading all those icons and junk, just… Just clean it, please.

11. Empty out the Trash (No, we're not joking…)

Seriously: It may sound incredibly basic, but it could clear a surprising amount of storage. I forget to do it all the time. The thing is, that when you delete something, your Mac doesn't remove it — it just moves it to the Trash. Plus, you've probably deleted way more than you realize, and all that could be sitting in the Trash, wasting space. So get rid of all that junk by emptying the Trash:

1. Ctrl+click your Trash in the Dock.
2. Select 'Empty Trash.'
3. And click 'Empty Trash.'

And, the easiest step is done.

A few more tips to clear storage on Mac

1. Manage your Optimized Storage

This option comes with your operating system starting macOS Sierra. Go to the Apple menu > About this Mac > Storage

Now, click on Manage to reveal the space-saving options:

2. Erase your Junk Mail

Open your Mail app, and click Mailbox in the upper menu. Here you can erase spam and already deleted items.

3. Delete system junk with CleanMyMac X
Again, this is an incredible utility when it comes to cleaning your startup disk. And this app is notarized by Apple, meaning it's safe.

To avoid the annoying 'your disk is almost full' error, download the free edition of CleanMyMac X.
Once you've installed the app, click on the System Junk tab. It will clean up caches, logs, language packs, binaries, duplicate photos, outdated backups, Trashes, and more.

Full Startup Disk Prevention

We've cleaned up a few things on your Mac, and hopefully, it's given you more ideas as to what else you can clean. But, let's take a look at how much space you saved from cleaning the list above. Remember how we checked your Mac's free space? Open that window again and see how much space you've cleared up:

1. Click the Apple Icon in the menu at the top-left corner of your screen.
2. Choose 'About This Mac.'
3. Click Storage.
   Note - If you are running an older version of OS X you may have to first click 'More Info…' and then 'Storage'.

You've probably got a bit more space, and you'll want to keep it that way. The only way to prevent a 'your disk is almost full' is by keeping your Mac clean. We'd recommend a complete cleaning every 2–3 weeks.

Say goodbye to the 'Your startup disk is almost full' message.

So, we've now covered everything that we wanted to share with you. Hopefully, this has helped you fix that full startup disk problem. Your startup disk should now be quite a bit lighter (we hope). Oh, and if you liked this article, get social with it to help others in need. And if you really liked this article, subscribe to our email list — we've got more guides on the way. And we've also got a utility that'll help you out a ton in the long run: CleanMyMac X. It helps you clean your entire Mac with just the click of a button. It's incredibly easy to use and works like a charm.

These might also interest you:

Optimised Storage in macOS Sierra and later* can save space by storing your content in iCloud and making it available on demand. When storage space is needed, files, photos, films, email attachments and other files that you rarely use are stored in iCloud automatically. Each file stays exactly where you last saved it, and will download when you open it. Files that you've used recently remain on your Mac, along with optimised versions of your photos.

* If you haven't yet upgraded to macOS Sierra or later, learn about other ways to free up storage space.

Find out how much storage is available on your Mac

Choose Apple menu  > About This Mac and then click Storage. Each segment of the bar is an estimate of the storage space used by a category of files. Move your pointer over each segment for more detail.

Click the Manage button to open the Storage Management window, pictured below. This button is only available in macOS Sierra or later.

Manage storage on your Mac

The Storage Management window offers recommendations for optimising your storage. If some recommendations have already been turned on, you will see fewer recommendations.

Store in iCloud

Macbook Startup Disk Missing

Click the Store in iCloud button and then choose from these options:

• Desktop and Documents. Store all files from these two locations in iCloud Drive. When storage space is needed, only the files you recently opened are kept on your Mac, so that you can easily work offline. Files stored only in iCloud show a download icon , which you can double-click to download the original file. Learn more about this feature.
  
• Photos. Store all original, full-resolution photos and videos in iCloud Photos. When storage space is needed, only space-saving (optimised) versions of photos are kept on your Mac. To download the original photo or video, just open it.
  
• Messages. Store all messages and attachments in iCloud. When storage space is needed, only the messages and attachments you recently opened are kept on your Mac. Learn more about Messages in iCloud.

Storing files in iCloud uses the storage space in your iCloud storage plan. If you reach or exceed your iCloud storage limit, you can either buy more iCloud storage or make more iCloud storage available. iCloud storage starts at 50 GB for $0.99 (USD) a month, and you can purchase additional storage directly from your Apple device. Learn more about prices in your region.

Optimise Storage

Click the Optimise button, then choose from these options.

• Automatically remove watched films and TV programmes. When storage space is needed, films or TV programmes that you have purchased from the iTunes Store and have already watched will be removed from your Mac. Click the download icon next to a film or TV programme to download it again.
  
• Download only recent attachments. Mail automatically downloads only the attachments that you have recently received. You can manually download any attachments at any time by opening the email or attachment, or saving the attachment to your Mac.
  
• Don't automatically download attachments. Mail only downloads an attachment when you open the email or attachment, or save the attachment to your Mac.

Optimising storage for films, TV programmes and email attachments doesn't require iCloud storage space.

Empty Bin Automatically

Empty Bin Automatically permanently deletes files that have been in the Bin for more than 30 days.

Reduce Clutter

Reduce Clutter helps you to identify large files and files you may no longer need. Click the Review Files button and then choose any of the file categories in the sidebar, such as Applications, Documents, Music Creation or Bin.

You can delete the files in some categories directly from this window. Other categories show the total storage space used by the files in each app. You can then open the app and decide whether to delete files from within it.

Learn how to re-download apps, music, films, TV programmes and books.

Where to find the settings for each feature

The button for each recommendation in the Storage Management window affects one or more settings in other apps. You can also control these settings directly within each app.

• If you're using macOS Catalina, choose Apple menu  > System Preferences, click Apple ID, then select iCloud in the sidebar: Store in iCloud turns on the Optimise Mac Storage setting on the right. Then click Options next to iCloud Drive: Store in iCloud turns on the Desktop & Documents Folders setting. To turn off iCloud Drive entirely, deselect iCloud Drive.
  In macOS Mojave or earlier, choose Apple menu > System Preferences, click iCloud and then click Options next to iCloud Drive. Store in iCloud turns on the Desktop & Documents Folders and Optimise Mac Storage settings.
• In Photos, choose Photos > Preferences and then click iCloud. Store in iCloud selects iCloud Photos and Optimise Mac Storage.
• In Messages, choose Messages > Preferences, then click iMessage. Store in iCloud selects Enable Messages in iCloud.

• If you're using macOS Catalina, open the Apple TV app, choose TV > Preferences from the menu bar and then click Files. Optimise Storage selects 'Automatically delete watched films and TV programmes'.
  In macOS Mojave or earlier, open iTunes, choose iTunes > Preferences from the menu bar and then click Advanced. Optimise Storage selects 'Automatically delete watched films and TV programmes'.
• In Mail, choose Mail > Preferences from the menu bar and then click Accounts. In the Account Information section on the right, Optimise Storage sets the Download Attachments menu to either Recent or None.

Empty Bin Automatically: From the Finder, choose Finder > Preferences, then click Advanced. Empty Bin Automatically selects 'Remove items from the Bin after 30 days'.

Other ways that macOS automatically helps to save space

Macbook Air Startup Disk Download

With macOS Sierra or later, your Mac automatically takes these additional steps to save storage space:

• Detects duplicate downloads in Safari, keeping only the most recent version of the download
• Reminds you to delete used app installers
• Removes old fonts, languages and dictionaries that aren't being used
• Clears caches, logs and other unnecessary data when storage space is needed

How to free up storage space manually

Even without using the Optimised Storage features of Sierra or later, you can take other steps to make more storage space available:

• Music, films and other media can use a lot of storage space. Learn how to delete music, films and TV programmes from your device.
• Delete other files that you no longer need by moving them to the Bin, then emptying the Bin. The Downloads folder is good place to look for files that you may no longer need.
• Move files to an external storage device.
• Compress files.
• Delete unneeded email: In the Mail app, choose Mailbox > Erase Junk Mail. If you no longer need the email in your Deleted Items mailbox, choose Mailbox > Erase Deleted Items.

Learn more

• The Storage pane of About This Mac is the best way to determine the amount of storage space available on your Mac. Disk Utility and other apps may show storage categories, such as Not Mounted, VM, Recovery, Other Volumes, Free or Purgeable. Don't rely on these categories to understand how to free up storage space or how much storage space is available for your data.
• When you duplicate a file on an APFS-formatted volume, that file doesn't use additional storage space on the volume. Deleting a duplicate file only frees up the space required by any data that you might have added to the duplicate. If you no longer need any copies of the file, you can recover all of the storage space by deleting both the duplicate and the original file.
• If you're using a pro app and Optimise Mac Storage, learn how to make sure that your projects are always on your Mac and able to access their files.