Freeing Up Space on a Mac: What’s Safe to Delete

2 Sep 2026

A Mac with very little free storage can become noticeably slower and less reliable.

Applications may take longer to open, macOS updates may fail, files may stop syncing, and the system may struggle to create temporary files or swap memory. You may also see repeated warnings that the startup disk is almost full.

The difficult part is knowing what can be removed safely.

Deleting personal files you no longer need is straightforward. Deleting unfamiliar folders inside macOS is not. The safest approach is to identify what is using the space, remove obvious clutter first and avoid system folders unless you understand exactly what they contain.

How Much Free Space Should a Mac Have?

There is no single perfect number, but a Mac should not be left with only a few gigabytes free.

macOS needs spare capacity for:

Temporary files
Software updates
Memory swap
App caches
Photos and cloud synchronisation
Spotlight indexing
Backups
System maintenance

As a practical target, try to keep at least 10–15% of the internal drive free. On a 512GB Mac, that means aiming for roughly 50GB or more where possible.

A small amount of free space may be enough for basic use, but it leaves very little room for updates or large applications.

Check What Is Using the Space

Open:

Apple menu > System Settings > General > Storage

macOS will analyse the drive and divide the storage into categories such as:

Applications
Documents
Photos
Music
Mail
Messages
iCloud Drive
macOS
System Data
Developer
Trash

The figures may take several minutes to update.

Use this page as a guide rather than assuming every category is completely accurate. Some files can appear under more than one broad label, and System Data is often a mixture of caches, logs, local snapshots and application support files.

Empty the Trash

Files in the Trash still occupy storage.

Open the Trash from the Dock and review its contents before emptying it.

To remove everything:

Finder > Empty Trash

Do not empty it without checking if you recently deleted something important.

Some applications also have their own deleted-items folders. Photos, Mail and cloud-storage services may retain deleted content separately for a period of time.

Start with the Downloads Folder

The Downloads folder is one of the safest places to look first.

It often contains:

Old installers
Duplicate documents
Disk images
Video files
Email attachments
ZIP archives
Temporary exports

Open Finder and select:

Downloads

Sort by Size or Date Added.

Files ending in these extensions are frequently safe to remove once they are no longer needed:

.dmg

.pkg

.zip

A .dmg file is usually an installer image. Deleting it does not uninstall the application that was installed from it.

A .pkg file is normally an installation package. Once the installation has completed successfully, the package is often no longer required.

Delete Old Installers

macOS updates and application downloads can leave large installers behind.

Look in:

Applications

for items named like:

Install macOS ...

These can use many gigabytes.

Delete an installer only when:

The upgrade has already completed
You do not need it to create recovery media
You are not planning to use it on another Mac

Third-party application installers in Downloads can also be removed after the application has been installed and tested.

Remove Applications You No Longer Use

Open:

Finder > Applications

Sort by size if helpful.

Large applications may include:

Games
Video editors
Music-production tools
Development environments
Virtualisation software
Microsoft Office
Adobe applications

To remove a simple application, drag it to the Trash.

However, some applications install:

Background services
Extensions
Licence managers
System components
Device drivers

Use the developer’s official uninstaller where one is provided.

Do not remove business security, backup or remote-management software unless you know why it is installed.

Review Large Files

From the Storage settings page, macOS may offer a file browser for reviewing large documents.

You can also search manually in Finder.

Open Finder, press:

Command + F

Set the search to This Mac, then add a filter for:

File Size is greater than

For example:

1 GB

Look for:

Old videos
Disk images
Virtual machine files
Database exports
Project archives
Duplicate backups
Large presentation files

Do not delete a large file simply because you do not recognise its name. Check its folder, creation date and associated application first.

Move Large Personal Files to External Storage

Files do not always need to be deleted.

Consider moving these to an external SSD or trusted cloud location:

Video libraries
Archived client work
Old photo collections
Completed projects
Music libraries
Virtual machine images
Large disk images

After moving a file:

Open it from the new location.
Confirm it works.
Make sure it is backed up.
Only then delete the original copy.

Moving the only copy of an important file is not a backup.

Photos Can Use a Huge Amount of Space

Open the Photos application and check for:

Large videos
Duplicate images
Burst photos
Screenshots
Screen recordings
RAW photographs
Recently Deleted items

The Duplicates section can help merge repeated photos and videos where available.

After deleting items, open:

Recently Deleted

and remove them permanently if you are certain they are no longer required.

Be careful with iCloud Photos. Deleting a photo on the Mac may also delete it from other devices connected to the same iCloud account.

Optimise Photo Storage

When iCloud Photos is enabled, you may be able to select:

Optimise Mac Storage

This allows macOS to retain smaller local versions while full-resolution originals remain in iCloud.

This can free substantial space, but it means some originals may need to be downloaded before editing or exporting.

Before enabling it, confirm that:

iCloud Photos has finished syncing
The correct Apple Account is being used
There is enough iCloud storage
Important photos are backed up independently where required

Cloud synchronisation is not the same as a complete backup strategy.

Check the Movies Folder

Open:

Finder > Movies

This folder may contain:

iMovie libraries
Final Cut Pro libraries
Screen recordings
Video exports
Camera imports
Old project media

Video-editing libraries can become extremely large because they may include:

Original media
Render files
Optimised media
Proxy files
Cache data

Use the application’s own storage-management tools before deleting anything inside a project library manually.

Remove Old Screen Recordings

Screen recordings are easy to forget and can use several gigabytes each.

Check:

Desktop
Movies
Downloads
Documents

Sort by size and look for .mov files.

Open them briefly to confirm they are no longer needed before deleting them.

Review Music and Podcasts

Downloaded music, podcasts and audiobooks can take significant space.

Check the relevant application’s download settings and remove offline content you no longer need.

Deleting a downloaded item does not always remove it from your library or purchase history. It may simply remove the local copy.

Confirm the difference between:

Remove Download
Delete from Library

These options can have different consequences.

Mail Attachments Can Accumulate

Mail may store downloaded attachments locally.

Large attachments include:

Videos
PDF bundles
ZIP files
Presentation files
Image collections

Search Mail for messages with attachments or large message sizes.

Delete messages only when you are certain they are no longer required and that retention rules allow it.

Business mailboxes may be subject to legal, compliance or organisational retention requirements.

Messages Can Store Large Attachments

The Messages application can retain:

Photos
Videos
Voice notes
GIFs
Documents

Check the Messages category in Storage settings or review conversations manually.

Deleting an attachment from Messages may remove it from the conversation on the Mac and potentially from synchronised devices.

Save anything important elsewhere before deleting it.

iCloud Drive Files May Be Downloaded Locally

Files stored in iCloud Drive may also have full local copies.

In Finder, right-click a file or folder and look for an option such as:

Remove Download

This removes the local copy while keeping the file in iCloud.

Use this only when:

The file has fully uploaded
You have internet access when you next need it
The cloud copy has been verified
The file is not required offline

Do not choose Move to Trash when your intention is only to remove the local download.

OneDrive, Dropbox and Google Drive

Third-party cloud services often provide an online-only option.

Depending on the service, the command may be called:

Free up space
Make online-only
Remove local copy
Smart Sync

Before using it, confirm that synchronisation is complete.

A file marked with an error or pending icon may not exist safely in the cloud yet.

Never delete the local version of an unsynchronised file.

What Is System Data?

System Data is a broad category rather than a single folder.

It may include:

Caches
Logs
Temporary files
Local Time Machine snapshots
Application support files
Fonts
Plugins
Virtual memory files
iOS device backups
Old update files
Developer data

Some of this is managed automatically by macOS.

A large System Data figure does not mean you should start deleting random files from the Library folders.

Is It Safe to Delete Caches?

Caches are temporary files designed to help applications load more quickly.

Many caches can be recreated, but deleting them indiscriminately can cause:

Slow application launches
Sign-in prompts
Lost offline data
Re-indexing
Application errors
Large re-downloads
Disrupted cloud sync

It is safer to:

Quit the affected application.
Use the application’s own cache-clearing option.
Delete only a cache linked to a diagnosed problem.
Restart the Mac.
Confirm the application still works.

Avoid deleting the entire contents of every Cache folder simply to recover space.

macOS will often rebuild caches, which means the recovered space may be temporary.

Avoid Deleting Files from the System Folder

Do not manually delete unfamiliar items from:

/System

or:

/private

or:

/usr

These locations contain essential operating-system components.

Modern macOS protects many system files, but changing permissions or using Terminal commands to force deletion can still damage the installation.

If an online guide instructs you to disable security protections merely to delete system files, stop and investigate further.

Be Careful Inside the Library Folders

There are multiple Library folders on a Mac.

User Library

~/Library

This contains data for the current user, including:

Application Support
Caches
Preferences
Containers
Mail data
Saved application state

System-wide Library

/Library

This can contain:

Application support files
Fonts
Launch agents
Drivers
Extensions
Shared components

Deleting the wrong item from either location can break an application or background service.

Do not remove entire folders simply because they are large.

Old iPhone and iPad Backups

Local device backups can use tens or hundreds of gigabytes.

Depending on the macOS version, you may be able to manage them through Finder:

Connect the device or open its Finder entry.
Select Manage Backups.
Review the dates and device names.
Delete backups that are definitely obsolete.

You can also check for backup data inside:

~/Library/Application Support/MobileSync/Backup

Do not manually delete individual files inside a backup folder. Remove the complete backup through the supported interface where possible.

Keep at least one valid backup if the device is not fully protected elsewhere.

Time Machine Local Snapshots

When a Time Machine backup disk is unavailable, macOS may retain local snapshots on the internal drive.

These snapshots are normally managed automatically and may be removed when storage is needed.

They can make used-space figures appear larger than expected.

Reconnect the Time Machine destination and allow a full backup to complete.

Do not use aggressive Terminal commands to remove snapshots unless there is a diagnosed issue and a verified backup.

Delete Completed Time Machine Backups Carefully

Do not delete folders directly from a Time Machine backup disk through Finder.

Time Machine backups use a structured system that can be damaged by manual deletion.

Use the supported Time Machine interface or erase and restart the backup set only when appropriate.

A backup drive should not be treated as ordinary spare storage.

Development Files Can Be Enormous

Developers may find a large Developer category.

Common storage users include:

Xcode simulators
Device support files
Build archives
Derived data
Package caches
Docker images
Virtual machines
Homebrew downloads

Xcode users can often remove old:

Simulators
Archives
Derived data
Device support files

Use Xcode’s own tools where possible.

Docker users should review containers, images and volumes carefully. Removing the wrong volume can delete development databases or project data.

Virtual Machines

Parallels, VMware Fusion and UTM virtual machines can consume enormous amounts of storage.

A single virtual disk may occupy hundreds of gigabytes.

Before deleting one:

Confirm the virtual machine is no longer required
Export any needed files
Check for snapshots
Verify licences and encryption keys
Confirm backups

Deleting a virtual machine package usually deletes the guest operating system and everything stored inside it.

Check for Duplicate Files

Duplicate files often build up after:

Repeated downloads
Manual backups
Folder migrations
Photo imports
Email attachments
Cloud-sync conflicts

Search by:

Filename
File size
Creation date
Modified date

Be cautious with duplicate-cleaning applications. Similar-looking files may be different versions or may belong to an application library.

Never allow a duplicate cleaner to remove files automatically without reviewing the list.

Clear Browser Downloads and Website Data

Browsers can store:

Downloads
Cached media
Website data
Offline content
Profiles
Extensions

Clearing browser cache may recover some space, but it can also sign you out of websites or remove offline data.

Check the Downloads folder separately, because clearing browser history does not normally delete downloaded files.

Remove browser profiles only when you have confirmed bookmarks, passwords and required data are synchronised or backed up.

Remove Old Printer and Scanner Software

Old device software can leave:

Utilities
Drivers
Update tools
Scan applications
Background agents

If the printer or scanner is no longer used, uninstall its software using the manufacturer’s instructions.

Do not manually delete driver files from Library folders unless the vendor specifically documents the process.

Logs and Crash Reports

Logs and crash reports usually do not use enough space to justify manual deletion.

If one application is generating huge log files repeatedly, the better fix is to identify why it is failing.

Repeated logging may indicate:

Permission errors
Failed cloud sync
Network retries
Database corruption
A broken extension
An application crash loop

Deleting the log without fixing the cause may only provide temporary relief.

Restart After a Major Cleanup

After removing a significant amount of data:

Empty the Trash.
Restart the Mac.
Reopen Storage settings.
Wait for the categories to recalculate.
Check that important applications still work.

The displayed free-space figure may not update instantly.

Avoid “One-Click” Cleaner Apps

Some Mac cleaner applications are legitimate, but others exaggerate problems or encourage unnecessary deletion.

Warning signs include:

Claims that thousands of harmless files are dangerous
Aggressive scare messages
Pressure to pay immediately
Removal of system files without clear explanations
Bundled browser extensions
Constant pop-ups
Requests for extensive permissions

macOS already includes useful storage-management tools.

A cleaner should never replace backups, proper diagnosis or manual review.

Never Delete Files You Do Not Understand from Terminal

Commands such as:

can permanently remove files without placing them in the Trash.

A mistyped path can delete far more than intended.

Do not paste storage-cleanup commands from unknown websites, especially commands using:

sudo

Administrator access does not make a command safe. It simply gives it more power.

When Storage Fills Up Again Immediately

If free space disappears shortly after cleanup, investigate:

A cloud-sync loop
A failed backup
Runaway log files
A virtual machine growing dynamically
Photo or video imports
Mail downloading large data
Local Time Machine snapshots
An application cache rebuilding excessively
Malware
A damaged file system

Open Activity Monitor and review the Disk tab to see which processes are writing large amounts of data.

A Safe Cleanup Order

Use this sequence:

Check Storage settings.
Empty the Trash after reviewing it.
Clean the Downloads folder.
Remove old installers.
Uninstall unused applications.
Review large personal files.
Move archives to external storage.
Remove unneeded videos and screen recordings.
Review Photos and Recently Deleted.
Remove local cloud downloads only after confirming sync.
Delete old iPhone or iPad backups.
Review developer files and virtual machines.
Restart and check the available space.
Investigate System Data only if it remains unusually large.
Avoid manual deletion from system and Library folders without a clear reason.

What Is Usually Safe to Delete?

Usually safe after reviewing:

Files in the Trash
Unneeded Downloads
Old .dmg and .pkg installers
Duplicate personal documents
Unwanted videos and screen recordings
Applications you no longer use
Old exported projects
Unneeded local device backups
Cloud files confirmed as safely uploaded
Completed archives stored elsewhere

What Should You Avoid Deleting?

Avoid deleting without expert knowledge:

Anything inside /System
Unfamiliar files in /Library
Entire folders inside ~/Library
Random caches in bulk
Time Machine backup folders
Unknown application-support files
Virtual machine files you have not inspected
Encryption keys and certificates
Mail databases
Photos library package contents
Files recommended by an untrusted cleaner app

Need Help Freeing Up Space Safely?

A full Mac can cause slow performance, update failures and application instability. The biggest files are not always safe to remove, and deleting the wrong application data can create more problems than it solves.

Hamilton Group can identify what is using the storage, remove unnecessary data safely and help you move large files to a suitable backup or cloud platform.

Call 0330 043 0069 or visit hgmssp.com to speak with one of our IT experts.

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