How to free-up / clear excessive "purgeable space" on HDD?

Question

How to free-up / clear excessive "purgeable space" on HDD?

I recently upgraded my 2010 Mac Pro from High Sierra to Mojave, and my next move will be to migrate from a mechanical HD to a SDD. To prepare for that, I moved about 100GB of old files (mostly disk images and other large files) to an external drive (physical drive connected to my Mac). I moved the originals of those backed-up files to the Trash and emptied it expecting to see 100GB more free space on my local hard drive. However, instead of reducing the used space by 100MB, the "purgeable" amount increased by 100MB!

I am not using iCloud or any remote cloud storage for back-up of any files, photo sharing, etc. My Time Machine back-up is also local on a second internal HD inside my Mac, so any solution that suggests the local purgeable space is caching or protecting photos and documents in iCloud doesn't apply here.

I intentionally and literally deleted 100GB of files that I no longer want to store locally on my HDD, so there is no reason that I need the OS to continue to store a hidden copy of them and not free-up drive space immediately. Although the purgeable space feature supposedly started with Sierra, I had never seen this OS behavior before upgrading to Mojave ... could this be related to Mojave changing my OS boot drive to APFS format during the upgrade? Can this be "undone"?

Another bad habit of Mojave is that the HDD is reading and writing continuously with the WARMD and MDS_STORES processes taking a lot of system capacity ... is this normal after 4~5 days since the Mojave upgrade?

Bottom-line, is there an OS setting or 3rd-party utility that can SAFELY return this HDD purgeable space to fully available? Do I need to downgrade to High Sierra? Thanks.

Posted on Feb 1, 2021 11:33 PM

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Answer 1

Feb 3, 2021 3:15 PM in response to Lee Warren 500

As a side-note, I accidentally "solved" the excess drive bashing and high disk activity from the WARMD process I experienced after my Mac Pro Mojave upgrade: It seems that when I upgraded from High Sierra to Mojave the OS installer also converted my mechanical HDD from HFS+ format to APFS format which is supposed to be optimized for use with SSD drives, not HDDs.

I don't know why the Mojave installer converted my hard drive to APFS format, but after I cloned that drive over to another drive that I intentionally pre-formatted to HFS+ (Mac OS Extended (Journaled) ), the excessive drive reading and writing stopped. The long boot delays and sluggish OS response completely stopped once the Mojave system was running on an HFS+ formatted drive. Bottom-line: AVOID using the APFS format for mechanical-based disk drives!

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Answer 2

Eau Rouge

Level 8

42,662 points

Feb 2, 2021 1:30 AM in response to Lee Warren 500

Where are you getting this information from, is it About This Mac> Storage, if so the information in there is often wrong.

Try rebuilding the Spotlight index,

How to rebuild the Spotlight index on your Mac – Apple Support

Move the Macintosh HD (or the name you gave your disk) in to the Privacy panel.

Quit System Preferences.

Open System Preferences> Spotlight> Privacy highlight Macintosh HD and press the minus button.

The mac will start rebuilding the Spotlight index.

Check by clicking on Spotlight in the menubar and enter word, if it is indexing you should see a progress bar.

If re-indexing has not solved your problem then run this app, https://www.omnigroup.com/more

this will give an accurate account of the storage used. When the app has created its overview you can look at

the Users folder in the output and see what each user has stored, you can then delete files from there.

Do not delete any files or folders in any System or Library folders or any files you do not understand.

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Answer 3

Feb 2, 2021 7:24 AM in response to Eau Rouge

Hi, Thank you for the helpful advice.

I had first tried the "About This Mac> Storage" route to look at the disk info, but it seemed to be very slow to show any useful information, so I was instead relying on the "Get Info" from the drive's icon. "Get Info" seemed to be accurately tracking the files being deleted (e.g. for every 10GB trashed & emptied, the purgeable space immediately increased by 10GB). After several reboots and about 12 hours of no change in the 100GB purgeable value, I had posted my original question.

Interestingly, this morning, now about 24 hours after deleting the files, this original 100GB of purgeable space has finally reduced to16GB, so the indexing already in-progress must have finally caught up. What I still find frustrating is the perpetual buzzing and churning of the mechanical HDD as the various background processes run continually since the Mojave upgrade. This aggressive disk activity makes my Mac very slow and unresponsive for several minutes after start-up and then randomly throughout the day. The WARMD process seems to be at-fault, but I've not found any good solution suggested for this except to upgrade to an SSD which will probably be my next step. Thanks again.

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How to free-up / clear excessive "purgeable space" on HDD?

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