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.
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 storage space appears when Optimize Mac Storage feature is turned on in About this Mac > Storage.
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.
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 two methods you can try to reduce and clear Purgeable space on Mac.
Use A Mac Cleaner - FonePaw MacMaster
One way to remove purgeable space on Mac is to delete files that may be counted as purgeable. FonePaw MacMaster can help you with that. The MacMaster 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 FonePaw MacMaster on your Mac.
Step 2 Run MacMaster. 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 MacMaster 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 MacMaster.
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.
The Terminal method is a little complicated if you know nothing about command lines. You can choose to get rid of Purgeable storage with FonePaw MacMaster, which is simpler and more effective.