It happens to everyone eventually. You’re in the middle of downloading a massive update or trying to save a client presentation, and that dreaded "Your disk is almost full" notification slides into the corner of your screen like an uninvited guest. It’s annoying. Honestly, it’s stressful because you know what comes next: the frantic hunt for what to delete. Most people just start dumping photos into the trash, but that’s rarely the real problem. If you want to clear space on a mac, you have to stop looking at your desktop and start looking into the digital corners where macOS hides its heavy lifting.
Apple’s file management has gotten better over the years, but it’s still surprisingly opaque. You check your storage settings and see a massive bar labeled "System Data" or "Other." What even is that? It’s a mix of cache files, old local Time Machine snapshots, and plugins you haven't used since 2019. This isn't just about making room for new files; it’s about making your machine feel snappy again. A choked hard drive is a slow hard drive.
The Massive "System Data" Mystery
Let’s talk about that "System Data" category. It’s the catch-all bucket for anything macOS doesn’t want to categorize as a Document, App, or Photo. Frequently, this is where your storage goes to die. If you’ve ever used professional creative software like Adobe Premiere or Logic Pro, these apps create massive "scratch disks" or cache files that stay on your drive long after the project is finished.
Check your Library folder. No, not the one you see in your user directory—the hidden one. Hold the Option key and click "Go" in the Finder menu bar to see it. Inside ~/Library/Caches, you’ll likely find gigabytes of junk. You can safely delete most of this, though your apps might take an extra second to load the next time you open them as they rebuild those files. It’s a trade-off. But when you’re down to your last 5GB of space, it’s a trade-off you’ll take every time.
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Another huge culprit? Local Time Machine snapshots. If you have Time Machine enabled but haven't plugged in your external backup drive for a few days, macOS saves "local snapshots" to your internal SSD. It’s supposed to delete them automatically when space gets low, but it’s not always as aggressive as it should be. You can force it to clear these out using Terminal commands, which sounds intimidating but is basically just telling the computer to do its chores.
Why Your Downloads Folder is a Graveyard
We all do it. We download a PDF, read it once, and leave it there forever. Or worse, we download a .dmg installer, install the app, and leave the installer sitting in the Downloads folder. Those installers are often several hundred megabytes. Do that ten times and you've lost a few gigs.
Go to your Downloads folder right now. Sort by file size. You’ll probably see a list of disk images, zip files, and forgotten attachments that are doing nothing but taking up space. It’s the easiest win. Just dump them. Honestly, if you haven't touched it in a month, you can probably download it again if you really need it.
The "Optimized Storage" Trap
Apple pushes "Optimize Storage" hard. The idea is that your Mac keeps your recent files on the drive and offloads the old stuff to iCloud. On paper, it sounds great. In practice, it can be a bit of a headache if you’re frequently offline or have a slow internet connection.
If you use iCloud Photos, ensure "Optimize Mac Storage" is checked in the Photos app settings. This keeps low-resolution versions on your device while the full-res originals live in the cloud. This single setting can save you 50GB or more if you’re a heavy photographer. Just remember: if you delete a photo on your Mac, it deletes from iCloud too. It’s a sync service, not a separate backup. People get that confused all the time and lose years of memories. Don't be that person.
Finding the Hidden Giants with OmniDiskSweeper
If you want to clear space on a mac like a pro, you need to see exactly where the bytes are. Standard macOS tools are a bit too "friendly" and hide the technical details. I always recommend a free tool called OmniDiskSweeper. It’s been around forever. It doesn't have a fancy UI, but it gives you a simple, tiered list of every folder on your drive sorted by size.
You might find that a random game you uninstalled three years ago left 10GB of assets in your Application Support folder. Or maybe a "mail.local" file has ballooned because of an indexing error. You won't find those by clicking around the Finder. You need a tool that drills down into the root directory.
Managing Your Mail
Speaking of Mail, if you use the native Apple Mail app and have multiple accounts, you’re likely hosting gigabytes of attachments. Every time someone emails you a 10MB PDF, it lives on your drive. Go to Mail > Settings > General and look at "Download Attachments." You can set this to "Recent" or "None" to stop your Mac from hoarding every single file ever sent to you. If you need an attachment, the app will just grab it from the server when you click it. It’s a much smarter way to work.
The iPhone Backup Problem
This is a big one. If you’ve ever backed up your iPhone or iPad to your Mac "just in case," those backups are massive. They are exact clones of your phone’s storage. If you have a 256GB iPhone, that backup could easily be 100GB.
Most people use iCloud for backups now, but those old local backups often linger.
- Open Finder.
- Click on your Mac in the sidebar.
- Under the "General" tab, click "Manage Backups."
- If you see an old backup from a phone you don't even own anymore, kill it.
Deep Cleaning the Caches
Browser caches are another sneaky offender. Chrome is notoriously bad at this. It’s a resource hog in every sense of the word. If you’re a heavy web user, your browser cache can easily hit 2GB to 5GB. Clearing your "Browsing Data" in Chrome or Safari is a quick fix, but it will log you out of most websites, so make sure you know your passwords before you nuking everything.
Also, consider your Trash. It sounds stupid, but people forget that moving a file to the Trash doesn't actually delete it. It just moves it to a different folder. If you have 20GB in your Trash, that’s 20GB still sitting on your SSD. Right-click that icon and empty it. It’s the digital equivalent of taking the garbage out to the curb.
Dealing with "Other" Storage and Language Files
Did you know macOS comes pre-loaded with files for dozens of languages you’ll never use? Every app you install likely includes localization files for Spanish, French, Japanese, and more. Individually, they’re tiny. Collectively, across hundreds of apps, they add up. There are utilities like Monolingual that can strip these out, but be careful—messing with app bundles can sometimes cause signatures to break, meaning the app won't open. It's a bit of an "advanced" move, but for those on a 128GB MacBook Air, every megabyte counts.
Practical Steps to Take Right Now
Stop reading for a second and actually do these three things. They take five minutes and usually yield the biggest results.
- Empty the Trash and Downloads: It's the "low hanging fruit" of disk management. Sort Downloads by size and be ruthless.
- Review Large Files: Go to the Apple Menu > System Settings > General > Storage. Click the "i" icon next to Documents. Look at the "Large Files" tab. If you see a movie you watched once in 2022, delete it.
- Check Your Desktop: Many people use their desktop as a temporary workspace. Over time, that "temporary" space becomes a graveyard of high-res screenshots and unorganized folders. macOS has to render every icon on your desktop, so a cluttered desktop actually slows down your system performance too.
The Reality of SSD Health
You shouldn't actually fill your SSD to 100%. Ever. Solid State Drives need a bit of "breathing room"—often called over-provisioning—to perform wear leveling. This is how the drive ensures it doesn't burn out specific memory cells by writing to them too often. Ideally, you want to keep at least 10-15% of your drive empty. If you’re consistently hitting 95% capacity, your drive’s lifespan is actually shortening, and its write speeds will plummet.
If you’ve done all the cleaning and you’re still struggling, it might be time for an external drive or a dedicated cloud solution for your "cold" data—the stuff you need to keep but don't need to access every day. High-speed external SSDs are incredibly cheap now compared to five years ago. Offloading your 500GB photo library to a dedicated external T7 or SanDisk drive is often a better solution than spending hours trying to delete tiny cache files.
Cleaning your Mac isn't a one-time event; it's maintenance. Just like you wouldn't let physical mail pile up in your hallway until you couldn't open the door, don't let digital junk pile up until your Mac stops working. Keep it lean.
Next Steps for a Cleaner Mac:
- Use the Storage Management tool built into macOS to identify the largest files currently sitting on your drive.
- Manually clear the ~/Library/Caches folder to reclaim space hidden by system processes and third-party apps.
- Relocate large media libraries, such as your Photos or Logic Pro Sound Library, to an external SSD to keep your internal drive under 80% capacity.