If you think that with Drag a file to the Recycle Bin and empty it; your data will disappear.It's time to change your mindset. On macOS, and even more so with macOS Tahoe, this deletion is purely logical: the system stops "seeing" the file, but the data is still there, ready to be recovered with basic software or, if needed, you can... Recover accidentally deleted files on MacIf you're going to sell your Mac, give it away, or simply handle sensitive information, this is a major privacy issue.
In this article you will see, step by step, How to securely erase disks and files in macOS Tahoe And recent versions: from completely wiping the disk with Disk Utility, to using Terminal, managing Time Machine local snapshots, what to do with SSDs and TRIM, how to leverage encrypted disk images, and when it makes sense to use third-party tools like MacGlacio. We'll also see how to reduce the massive "System Data" files that take up hundreds of GB.
Why deleting "normal" in macOS isn't enough
When you empty the Trash on your Mac, the data is not destroyed.What macOS does is remove the file reference from the file system (the "library entry") and mark that space as available. The actual content remains on the disk until it's overwritten with other data, which can take weeks, months, or even years if you have a lot of free space.
Imagine the record as a huge library full of booksSaving a file is like putting a book on a shelf and creating a catalog entry. When you delete it, you only break the entry; the book remains on the shelf. A data recovery program is essentially someone who walks the aisles and retrieves books even without catalog entries.
This means that anyone who has physical access to your Mac (Because you sell it, give it away, or simply lend it out) you can use recovery tools to retrieve old documents, personal photos, bank statements, work reports, or scanned copies of your ID cards. You don't need to be a hacker: there are "click and go" utilities capable of reconstructing much of what you've deleted.
In professional environments the problem is even more serious: Poor erasure can lead to non-compliance with regulations. of data protection (privacy, sector regulations, contracts with clients…), with the possibility of fines and legal liabilities if that data ends up in the wrong hands.
The type of disk also mattersIn a traditional HDD (mechanical hard drive), magnetic data remains intact until explicitly overwritten, making recovery usually very effective. In modern SSDs, the TRIM command internally erases cells when the system marks blocks as free, complicating recovery but not always making it impossible or guaranteeing a "military-grade" erasure. For truly sensitive data, it's advisable to go a step further.
How to securely erase a disk in macOS Tahoe using Disk Utility
If you would like to leave an internal or external disk completely clean (For example, to sell your Mac or reuse a drive.) If you're going to recycle it, see what to do with an old MacBookThe key tool is Disk Utility. However, there are important differences between erasing the boot disk and any other volume.
Erase the startup disk from macOS Recovery
To format the disk where macOS Tahoe is installed, you need to Start your Mac in Recovery modebecause you can't delete the volume you're booting from:
- Shut down your Mac and turn it on using the correct keyboard shortcut to enter macOS Recovery (this varies depending on whether it's an Intel or Apple Silicon model). Follow Apple's instructions for your specific model.
- On the utilities screen, select "Disk Utility" and click Continue.
- In the sidebar, select the primary volume (usually named “Macintosh HD” or something similar). If you don’t see it, make sure “Show All Devices” is selected in the View menu.
- Click on the Delete from the toolbar.
- Enter a name for the disk (for example, “Macintosh HD”) and choose the recommended format, which on modern computers is usually APFS or, on older systems, “Mac OS Plus (Journaled)”.
- If the option appears, choose “Delete volume group” To clear all associated volumes. Otherwise, simply click Delete.
- If prompted, enter your Apple account information to unlock the drive.
- When the process is complete, close Disk Utility to return to the Utilities window and choose "Reinstall macOS" if you want to prepare it for the next user.
This process erases the logical content of the volume, but in many cases it's a good idea Apply secure erase options on mechanical disksespecially if the team is going to change hands.
Erase with security options (some disks only)
When working with a traditional hard disk drive (HDD) or certain external drives—and if you are going to format a drive, consult Format a USB drive on a Mac—, Disk Utility offers a button called "Security options" By pressing Erase on the physical device (not just the volume). This allows you to choose how many overwrite passes are applied when erasing:
- Faster: write zeros once over the space, it's better than a simple erase but it's not the most paranoid option.
- Intermediate level: three passes, balancing safety and time.
- Safer: up to seven passes, following patterns similar to defense standards, designed to make recovery extremely difficult.
To use it, select it in the sidebar. the complete device (the highest entry in the hierarchy, usually with the manufacturer's name), press Delete, choose "GUID Partition Map" scheme, an appropriate format, and, if you see the button, go into Security Options to choose the desired level.
Note that Secure erase options are not available for all disksOn most modern SSDs, the button doesn't even appear, precisely because of how they internally manage blocks and the TRIM command. In those cases, the combination of encryption and a simple erase is usually more effective than trying to physically overwrite a thousand times.
Advanced file and disk management: Terminal, TRIM, and encrypted images
If you want to go a step further or have more specific needs, macOS offers advanced tools for handling sensitive filesSome are still available as standard, while others require some imagination or third-party software, for example. MacCleanse.
Using Terminal to delete files in a more controlled way
In older versions of macOS, the command existed SRMThis feature was designed to delete files by overwriting their data multiple times before removing them from the file system. Apple discontinued it starting with macOS Sierra, partly due to the rise of SSDs, where an exact physical overwrite cannot be guaranteed.
Today you can still use Terminal for deleting files in a more controlled way with the command rmand in many versions the option is still available -Pwhich attempts to overwrite before deleting: rm -P nombre_del_archivoFor other alternatives and tricks, see how Always empty your Recycle Bin safely.
To make your life easier, you can enable the option in System Preferences > Keyboard > Shortcuts > Services “New terminal in the folder”Thus, by right-clicking on a folder in Finder and entering Services, you'll have a Terminal window already pointing to that path to execute commands like ls (list) and rm -P about the files you want to remove.
Yes, Terminal does not forgive mistakesA mistyped command can delete the wrong folder with no way to undo it. Therefore, for non-advanced users, a little caution is always recommended, and if possible, a backup should be made beforehand.
TRIM on SSD: what it does and what it doesn't do
Macs with SSDs have a feature called TRIMThe main purpose of this is to maintain the drive's performance. What the operating system does is inform the SSD which blocks are no longer in use (because you've deleted files, for example), so the drive itself can erase those cells in the background and optimize future writes.
In recent macOS versions, TRIM is usually enabled by default on Apple SSDsIf you're working with a third-party SSD, you can use Terminal to force its activation with:
sudo trimforce enableThe system will show you a warning that Functionality is not guaranteed with all units and that you use it at your own risk. After accepting, your Mac will restart to apply the change. Before experimenting with this, it's a good idea to have a full backup, just in case.
TRIM makes data recovery on SSDs much more complicated, but It is not a perfect substitute for a classic secure eraseYou can't precisely control how and when the cells are cleaned internally, and traces can always remain. For highly sensitive information, the most robust strategy is usually to use encryption (FileVault or encrypted volumes) and destroy the key when you no longer want the data to be accessible.
Use an encrypted disk image to manage sensitive files
One smart way to reduce risk is Always work with sensitive files within an encrypted disk image And when you no longer need them, just delete that image. That encrypted .dmg file will contain all the data, and without the password it's virtually unrecoverable.
macOS lets you easily create them from Disk Utility:
- Open Disk Utility (from Spotlight, the Utilities folder, or with the shortcut ⇧ + ⌘ + U).
- In the File menu, choose New image > Empty image.
- Specify a name for the image, a location, a maximum size, and the desired format.
- In the Encryption field, select 128 bit AES Or, if you want more security and accept slightly less performance, 256-bit AES.
- Enter a strong password, disable the option to save it to the keychain if you want maximum protection, and save the image.
When you open the image, it will mount as an additional volume in Finder. You can drag all the compromised documents thereWork with them, and when you're finished, eject the volume and delete the .dmg file when you no longer need it. Even if someone recovers a deleted .dmg file, it will still be encrypted, and without the password, they won't be able to see its contents.
Free apps and automation for better deletion
There are free macOS apps that integrate with the Finder and offer "more serious" deletion options than to throw in the trash, like Trash It 5.0They usually allow you to define the number of overwrite passes, add an "Erase" item to the Services menu, and automate tasks.
An interesting approach is to combine one of these apps with automator To create small workflows: for example, an application that takes selected files in the Finder and sends them directly to the secure deletion tool. Then you can drag that app to the Dock and use it like any other icon to shred sensitive files.
Even so, it must be remembered that Generic solutions do not always guarantee total securityespecially on SSDs. They are a big step up from normal erasure, but for high-risk scenarios, professional erasure tools should be considered.
The massive “System Data” in macOS Tahoe and how to reduce it
One of the most frequent headaches in macOS Tahoe, Sequoia, Sonoma, Ventura, and Monterey is opening the Storage tab and seeing a dark gray "System Data" bar swallowing hundreds of gigabytesThis category mixes caches, logs, backups, support files… and often grows uncontrollably, so it's worth taking care of. enable automatic cleaning of temporary files where applicable.
When “System Data” is triggered, the Mac can running out of free space and becoming slowwith errors when syncing with Dropbox, problems updating applications, or installing new versions of macOS. The key is to understand what's behind it and address the main culprits.
Time Machine Local Snapshots: The Silent Culprit
One of the factors that most inflates this section is the Time Machine local snapshotsWhen you have Time Machine set up and the backup disk is not connected, macOS creates copies on the internal drive itself, which are theoretically freed up when space is needed… but it doesn't always happen as we would like.
It is relatively common to find cases in which a single local snapshot takes up hundreds of gigabytes and it appears in the System Data. The good news is that you can list and delete them with a few commands in Terminal, even if you're not very tech-savvy.
The basic steps would be:
- Open Terminal (the quickest way is to press ⌘ + space, type “Terminal” and press enter).
- List local snapshots with:
tmutil listlocalsnapshots / - You'll see names like this.
com.apple.TimeMachine.2026-01-123456.local. - To delete a specific snapshot:
tmutil deletelocalsnapshots NOMBRE
replacing NAME with the corresponding numerical part. - Run again
tmutil listlocalsnapshots /to check what's left.
There is also a massive “weight loss” command, of the type sudo tmutil thinlocalsnapshots / 9999999999 1designed to force cleaning. In practice, It doesn't always work equally well in all casesTherefore, deleting snapshots individually is usually more reliable.
Once you've freed up that space, you might be interested in Disable Time Machine automatic backups If you don't want them to be generated again:
- In macOS Ventura, Sonoma, and later: System Settings > General > Time Machine > Options… and select “Manually” for Backup Frequency.
- In Monterey and earlier: System Preferences > Time Machine and uncheck “Back up automatically”.
System junk, caches, and logs
Over time, the apps and the system itself accumulate caches, logs, temporary files, and remnants of partially uninstalled applicationsIndividually they are not dramatic, but together they can add up to several gigabytes (or tens) in System Data.
For easier cleaning, there are tools such as iBoysoft Cleaner or others of its kind, which analyze the entire disk, list large files, caches, files in Downloads, app remnants, disk images… and allow you to select what to delete without having to go folder by folder; you can also consult our list of best apps for Mac to evaluate options.
If you prefer a manual approach, the classic directories where application debris accumulates are:
~/Biblioteca/Caches~/Biblioteca/Preferences~/Biblioteca/Application Support~/Biblioteca/Logs~/Biblioteca/Saved Application State~/Biblioteca/Containers~/Biblioteca/Cookies~/Biblioteca/LaunchAgentsand their equivalents in/Bibliotecafor system-level agents and daemons.
The trick is in Only delete what truly belongs to apps you no longer useRandomly deleting files in these paths can break configurations or cause strange behavior, so it's best to proceed slowly or use specialized tools.
Old iOS backups and other “hidden” items
If you've used your Mac to do iPhone, iPad, or iPod touch backupsIt's likely you still have very old backups taking up a huge amount of space. Those backups also count towards System Data.
From macOS itself (in the Finder or the device management app, depending on the version) you can List associated iOS backups and delete the ones you no longer need. It's a good habit to review this section from time to time, especially if you've had multiple devices over the years. If you're going to erase an iPhone, consult the Guide to securely erasing your iPhone.
It's also worth taking a look at less obvious elements such as dynamic screen savers (on macOS Sonoma and later). Some of these screensavers are high-quality videos that can be hundreds of MB each; if you try many, they can easily add up to several GB in your system data. You can delete the ones you don't use and download them again later if you miss them.
Optimize storage and empty the Recycle Bin (even though it sounds basic)
Although it may seem obvious, Emptying the Recycle Bin remains one of the fastest ways to reduce system dataUntil you do that, those files continue to occupy entire disk space, even though you no longer see them in your usual folders.
In addition, macOS includes a number of features in the Storage section. optimization recommendations very useful:
- “Store in iCloud”: Moves infrequently used files and photos to the cloud, keeping optimized versions on your Mac when space is limited.
- “Optimize storage”: automatically removes movies and TV shows from the TV app that you have already watched.
- “Empty the Recycle Bin automatically”: permanently deletes anything that has been in the Recycle Bin for more than 30 days.
These measures do not replace secure deletion when dealing with critical information, but They are very helpful in keeping "System Data" under control. so the Mac can breathe better.
Why and when to use professional secure erasure software (MacGlacio and company)
macOS's built-in tools, while useful, have fallen short in terms of truly secure and verifiable deletionApple removed features such as secure Trash emptying and commands srm Precisely because SSDs cannot guarantee exact block overwriting. This leaves a gap that third-party solutions fill.
Professional file shredding programs offer military or government-grade data destruction methodsThese methods, such as the DoD 5220.22-M standard or the Gutmann method, perform multiple overwrite passes with specific patterns and verification checks. They typically allow for the secure deletion of individual files, entire folders, or the entire free disk space.
One of the specific proposals for Mac is MacGlaciodesigned for those who want finer control over how their data is destroyed:
- It includes 51 advanced crushing methods, from quick one-pass options to standards used by government agencies.
- It not only destroys the content, but also Remove metadata, attributes, and path namesfurther reducing the traces.
- It incorporates its own intelligent method (“Wiper”) that It adapts to the file and storage type. to balance safety and hardware wear.
- It works with both HDDs and SSDs, internally adjusting the focus according to the drive.
Its layered process combines reads, writes, overwrites, and checks to ensure that the file is unrecoverableAnd yet, it maintains a simple interface so that any user can use it without needing in-depth technical knowledge.
Beyond MacGlacio, the key idea is that There is a huge difference between “deleting” and “securely deleting”If you manage corporate documents, customer data, medical records, financial files, or any information that could cause you serious problems if it falls into the wrong hands, investing in a tool like this is much cheaper than dealing with the consequences of a failure.
For everyday use, the Trash, Disk Utility, and occasional cache clearing might suffice. But at key moments (before selling your Mac, when recycling a disk, after completing a confidential project, or when a data retention period expires), Secure erasure is no longer optional; it's almost mandatory. if you want to sleep peacefully.
Taking all of this into account, the combination of Up-to-date backups, proper use of Time Machine, regular system data cleanup, leveraging encrypted images, and, when necessary, professional data erasure toolsIt allows you to keep your Mac fast, with enough free space and, above all, without leaving your digital life accessible to anyone every time you press delete or decide to change computers.