- The Macube Cleaner cleaner can free up space on your Mac disk by deleting system cached files, logs, duplicate files, large or old files, mail caches/attachments, etc. It makes it simple to remove purgeable files on Mac. Step 1 Download and install Macube Cleaner on your Mac. Step 2 Run Macube Cleaner.
- Add, delete or erase APFS volumes in Disk Utility on Mac. Apple File System (APFS) allocates disk space on demand. When a single APFS container (partition) has multiple volumes, the container’s free space is shared and can be allocated to any of the individual volumes as needed.
- How To Wipe A Mac Hard Drive
- Erase Free Space On Mac
- Mac Erase Free Space Ssd
- Secure Erase Free Space
- Mac Terminal Erase Free Space
You’ll also want to read “OS X: About Disk Utility‘s erase free space feature. ” A note at the end starts to get to the heart of the matter. With an SSD drive, Secure Erase and Erasing.
In a Mac running on macOS Sierra, High Sierra, Mojave, you'll find a part of the Mac storage space is calculated as purgeable storage. What does purgeable mean on Mac hard drive? And more importantly, with purgeable files taking up a substantial amount of storage space on Mac, you might not be able to download a large file, install macOS update or install a certain app. So how to remove purgeable space on Mac?
Since there is no option on the Mac to find out what purgeable space is or to delete purgeable space, you need the following tips to help you get rid of purgeable storage on Mac.
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What Is Purgeable Space on Mac?
How To Wipe A Mac Hard Drive
Purgeable storage space appears when Optimize Mac Storage feature is turned on in About this Mac > Storage.
Unlike Applications, iOS Files and other kinds of storage which allows us to view what files are taking up that storage space, Purgeable storage doesn't list out all the purgeable files on the Mac. So there is no way to find out what exactly Purgeable storage contains.
Generally, as its name has suggested, purgeable space is the storage space holds files that can be purged by macOS when free storage space is needed. Files marked as purgeable can be things such as:
Photos, documents that are stored in iCloud;
Purchased movies and TV shows from iTunes you've already watched and can be re-downloaded;
Large fonts, dictionaries, language files that you may never or rarely use;
System caches, logs, duplicated downloads from Safari ...
Purgeable Space Is Not Really Free Space
The available storage space of your Mac is made up of free space and purgeable space, for example, if you have 10GB free space and 56GB purgeable space on Mac, the total available space is 66GB. Purgeable space is not empty space. In fact, the purgeable files are actually taking up space on your disk. How Purgeable storage works is that when you need to download, for example, a file of 12GB, the macOS system is designed to remove some of the purgeable space to make room for the 12GB that you are going to download.
However, purgeable storage doesn't always work as expected. Sometimes, you find that you can't download a file of 12GB because your Mac says that your disk is almost full and there is 'not' enough disk space, while you can see there is 56GB purgeable space in Storage.
How to Delete Purgeable Space on Mac
It is difficult to clear Purgeable space on Mac because it is the macOS to decide what files are purgeable and when to purge these purgeable files. Users can't control when to delete purgeable storage space on Mac (and Apple suggests that you don't need to delete purgeable storage on Mac manually). However, if you are really troubled by a large amount of storage space that is taken by purgeable data, here are four methods you can try to reduce and clear Purgeable space on Mac.
Use Macube Cleaner to Clear Purgeable Space on Mac (Recommended)
One way to remove purgeable space on Mac is to delete files that may be counted as purgeable. Macube Cleaner can help you with that. The Macube Cleaner cleaner can free up space on your Mac disk by deleting system cached files, logs, duplicate files, large or old files, mail caches/attachments, etc. It makes it simple to remove purgeable files on Mac.
Step 1 Download and install Macube Cleaner on your Mac.
Step 2 Run Macube Cleaner. You should see the usage of storage space, memory space, CPU.
Step 3 You can choose todelete the items that are clogging up your memory space. For example:
- Click Junk Files. You can clean system caches, logs, app caches which may be considered as purgeable by Mac.
- Click Large & Old Files, which may contain large files that are in Purgeable space. Choose all the photos, documents, movies or other files that you don't need and click Clean to remove them.
- Click Duplicate Files, where you can remove duplicated files on Mac to free up Purgeable space.
Just follow the scanned result of Macube Cleaner to clean out all the files that you don't need. After that, go to About this Mac > Storage, you'll be happy to find that you have reclaimed lots of Purgeable space with Macube Cleaner.
Delete Purgeable Space on Mac by Rebooting Your Computer
If you prefer to do the purgeable space deletion manually, an easy way to free up storage space that people usually forget is to restart your computer. You may rarely do this but it can actually reclaim some purgeable disk space that is occupied by system caches or application caches. If you have not rebooted your Mac for a long time, the amount of the purgeable memory can be large. Just click the Apple logo on your top menu bar and tap Restart, you may happy to see more space available on your Mac.
Remove Purgeable Space on Mac by Using Mac Recommendations
Though Apple doesn’t show you what purgeable space is, it also provides options for you to optimize your Mac storage space. Click the Apple logo at the top menu > About This Mac > Storage > Manage, you will see a few recommendations for you to manage the storage space on Mac.
Store in iCloud: This feature helps you transfer purgeable files to iCloud including files on Mac in Desktop and Documents, your photos and messages. Only the recently opened and used ones are saved locally.
Optimize Storage: The iTunes films and TV programs that you have already watched will be removed as the purgeable space.
Empty Trash Automatically: Purgeable files stored in Trash for more than 30 days will be removed.
Reduce Clutter: The files that take up large space on your Mac will be identified and you can manually select and delete to release purgeable space.
Delete Purgeable Space on Mac by Creating Large Files
Since purgeable space won't be removed until macOS thinks that it needs to make free space for new apps or files, some users developed the idea to create enough large files to reclaim the space taken up by purgeable files. Here are the steps.
Step 1 Launch Spotlight and enter Terminal. Open Terminal.
Step 2 In the Terminal window, enter the line: mkdir ~/largefiles and hit Enter. This creates a new folder called 'largefiles' on your disk.
Step 3 Then perform the line: dd if=/dev/random of=~/largefiles/largefile bs=15m, which will create a new file called 'largefile'of 15MB in the largefiles folder. This could take a while. After about 5 minutes, hit Control + C in the terminal window to end the command.
Step 4 Then perform the command like cp ~/largefiles/largefile ~/largefiles/largefile2, which will make a copy of largefile named largefile2.
Step 5 Continue to make enough copies of the large files by running the cp command. Note that you should change the name of to largefile3, largefile4, etc. to make different copies.
Step 6 Keep running the cp command until it returns with a message indicating that the disk is critically low from Mac.
Step 7 Run the command execute rm -rf ~/largefiles/. This will delete all of the largefiles you have created. Empty the files from Trash as well.
Now go back to About this Mac > Storage. You should notice that Purgeable storage is removed or reduced.
Wrap Up
Above are the 4 ways that you can clear purgeable space on Mac. Rebooting your Mac or using Mac recommendations are reliable and easy but may not go deep enough. The Terminal method is a little complicated if you know nothing about command lines. If your free space on Mac is not enough after trying rebooting and recommendations, you can choose to get rid of purgeable storage with Macube Cleaner, which is also simple and more effective.
| Click here to return to the 'Erase free disk space from the command line' hint |
Wouldn't you be much better off using /dev/random instead?
'Wouldn't you be much better off using /dev/random instead?'
No, that would actually be terrible. First of all, you shouldn't fill the boot disk of a running machine because it will cause problems, so the hint is a bad idea anyway. However, if you are anxious to do bad stuff like fill your root drive, then you definitely shouldn't do it from /dev/random, because /dev/random requires vastly more CPU power to generate data for than /dev/zero does. If would take few hours to fill a drive from /dev/zero, but it could take a few weeks to fill it from /dev/random.
Also, I don't know if Mac OS X does this, but Linux will sometimes block on reads from /dev/random while it waits for more genuinely random input from the outside world (say mouse movements, or network traffic rates or some such). (This used to cause 'depleted entropy pool' problems for ssl and ssh on linux. Sorry for the 'in my day' storry, but I remember when I used to use linux to generate SSH keys and I would have to wiggle my mouse around a lot in order to generate ssh keys in a reasonable amount of time. :-)
Yes, I remember when I setup a FreeBSD server ~5 years ago, I got the standard generating key message you would normally get, then something odd telling me to 'wiggle my mouse or hit keys on the keyboard'. You feel like an idiot standing at a console in the server room, 'wiggling the mouse', and banging on the keyboard, with other admins* walking around asking you if you have gone insane.
Its funny now, not so much back then.
* They were Windows admins, I was the *nix admin at that time.
Firstly one does not run this as root. run this as a normal user. The system reserves some space for the root user, and this way you will not run out of disk space for critical system. (At least I know this to be true for reiser, ext3 and ext2 filesystems on Linux.
Secondly, anyone paranoid enough to want to do it should never use /dev/zero (Not even when doing it multiple times) since you can still get the data using forensic techniques. Even if you do this multiple times... some drives with advances caching may not even do the successive writes on a very low level (even with only a small sized disk-cache).
Lastly, yes, /dev/random is more cpu intensive... as for a lot more? No it does not:
I did:
(cat /dev/zero > zero &) ; (cat /dev/random > random &) ; sleep 20 ; killall cat ; ls -l zero random
And it showed:
joseki:~ marius$ ls -la random zero
-rw-r--r-- 1 marius staff 222302208 Apr 24 12:27 random
-rw-r--r-- 1 marius staff 666898432 Apr 24 12:27 zero
So, yes, I would suggest using random... a good system-wide anti-entropic engine should be pretty efficient.
As UNIX SysAdmin, I don't think this makes any sense at all.
First, filling up your drive is a very bad idea, as Rob points out. Many services will stop functioning or exhibit odd behavior.
Secondly, I'm not quite sure what you're trying to do here? Make sure any unused sectors are zero'd out? I'm guessing you're using secure delete already anyways. This just doesn't make any sense. Do you work for the NSA? Didn't think so. You don't need to 'zero' your unused disk space.
P.S. - This '35 pass delete' stuff is B.S. The only way to recover data from a HD after 3 passes is with a team of people and highly specialized hardware. Sorry everybody, but my guess is that your data is not that important. Save your hard drive life and stop using 35-pass deletes. If you have sensitive data, encrypt it using a strong passphrase and you'll be much better off.
---
Nem W. Schlecht
http://geekmuse.net/
Not only is this not a good idea, it doesn't entirely work as advertised. Realize that changes to files are often not written to disk immediately. Instead, they are held in memory (cached) and queued for writing to disk. So, when your cat command dies due to insufficient space, it's likely that some of the writes have not completed. When the file is removed, those writes can be deleted from the queue of pending writes. Consequently, some of the disk blocks will never be overwritten.
Also, many filesystems limit the amount of disk that a regular user (i.e. not root) can write to. For instance, UFS reserves 10% of a filesystem (by default, can be set with tunefs minfree option) for root. This would mean that the above command would fail after writing to 90% of the disk, not 100% (leaving 10% unwritten). Unfortunately, I'm not familiar with the implementation of HFS+, so I can't comment on whether it has similar behavior.
'Do you work for the NSA? Didn't think so. You don't need to 'zero' your unused disk space.'
I'm guessing you know the things I'm about to say already and just didn't think about them when you wrote this, but using secure erase means that Finder is configured to do secure erase when it empties the trash. It has no impact on, say Quicken's temporary files in /tmp . File in /tmp are also outside of the user's FileVault (assuming this person is using FileVault). There have also been multiple cases where people have suffered identity theft after their financial information was lifted from old drives despite the fact that it had already been (insecurely) deleted on the old drive.
With that said, FileVault, secure erase, and encrypted VM will cover the vast majority of people's needs. In fact, simple lack of familiarity with HFS+ on the part of thieves will cover a lot. Nonetheless, there are legitimate cases for a non-FBI-employee to want to erase the blank space on a root drive.
some of us do. given, this isn't the best way to go about it, it would help prevent some data recovery.
if you want to use this method, i would recommend booting into single use mode first. (cmd-opt-s)
diskutil is the correct way to do this.
------
Disk Utility Tool
Usage: diskutil secureErase [freespace] level
MountPoint|DiskIdentifier|DeviceNode
Securely erases a disk or its freespace.
Level should be one of the following:
1 - Single-pass randomly erase the disk.
2 - US DoD 7-pass secure erase.
3 - Gutmann algorithm 35-pass secure erase.
Ownership of the affected disk is required.
Example: diskutil secureErase 2 /dev/disk2
Note: Level 2 or level 3 secure erases can take an extremely long time.
er,
diskutil secureErase freespace 1 /dev/xxx
Erase Free Space On Mac
rm call might not complete. In a ram-tight situation (if, say, the filesystem cache were to get rather large), then a fork might fail if there's no room on the swap device for more vm. JP---
Pell
As robdew pointed out, you can do this with diskutil. A good rule of thumb is that if Disk Utility can do it, diskutil can do it.
In fact, Apple is great at letting you do anything (and more!) from the command line - for example, the 'softwareupdate' command for auto-updates.
Mac Erase Free Space Ssd
The right method to perform this very action is part of diskutil:
diskutil secureErase freespace 1|2|3 /dev/disk#s#
(See the man page on diskutil)
Band-aids never work right. They always peal off!
But that won't work unless you have root access, right?
This command does exactly what Disk Utility does. If your computer crashes during a wipe of the free space, you will find that your hard disk space is reduced. Removing the zeroed file from /tmp (if I remember correctly) will restore the disk space. Try doing it in Disk Utility and watch your disk space shrink.
As others have pointed out, some disk space is reserved for root, and therefore the chance of a crash is minute.
Thanks, robdew, for pointing out the secureErase option of diskutil. Some how I missed that. It does exactly the same thing.
Secure Erase Free Space
...if you're concerned about running the aforementioned 'erase free space' operation on a 'live' filesystem, you may want to shut down your system and reboot with your OSX install disc and run Disk Utility from there instead.
Or, (in keeping with the spirit of the original hint of using the cmd-line) reboot with your OSX install disc into Single User mode (documented elsewhere) then use the diskutil tip mentioned earlier.
Mac Terminal Erase Free Space
Get the name of your disk (probably /dev/disk0s2) and type the diskutil command to erase free space which is:
diskutil secureErase freespace 1 /dev/disk0s2 That will erase your free space with random numbers. See the list of options below:
Level should be one of the following: 0 - Single-pass zeros.
1 - Single-pass random numbers.
2 - US DoD 7-pass secure erase.
3 - Gutmann algorithm 35-pass secure erase.
4 - US DoE 3-pass secure erase.