How to delete purgeable space on external SSD?

I have an external SSD where I want to install Big Sur beta. It would not install because it wanted an extra 20GB space. I have now deleted 50GB and emptied the trash, but the deleted space is showing as purgeable, and the installer still does not see the space as available.

Yes, I could erase the disk. But I don’t want to because I’d rather experience Big Sur with the data that is on the disk.

How can I reclaim this purgeable space on an external SSD?

Answered my own question, leaving it here in case others need it later: DaisyDisk, but not the Mac App Store version. Since I have the MAS version, I downloaded the free trial version and that did it. Thankyou DaisyDisk!

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You mean the App Store version wouldn’t do it? That seems weird.

It’s understandable. Apple would not allow it on the App Store if it did something that Apple would not allow. iStat Menus has similar issues which they get around by providing a free download that provides the forbidden functions if you buy the App Store version.

So, is there a bug here with the original problem? Purgeable space is supposed to be released as needed, but the Big Sur installer could not use it.

But on the Mac there are mechanisms already in place to let the user enable the necessary functionality: Full Disk Access, for one.

I’m not sure that Full Disk Access would allow low level access like purging space and whatever it is that iStat Menus can’t do from the MAS version (read temperature sensors? set fan speed based on temperature? can’t remember).

You are correct on both counts:

What a nuisance.


sometimes ago there was a procedure (in app) to get the standalone versione from the App Store version, to let it run wit less constraint… it might be worth checking :smiley:

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Found and obtained, on the page provided by @jec0047 thanks both!

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Thanks for sharing!

Has this reply reached 20 characters yet??? Haha…

Back reading my own post. I’m trying to increase the free space on my 1TB internal SSD. I have deleted 100GB of files, some regular files and a device backup, every time I have emptied trash and every time DaisyDisk reports increased hidden space and I don’t get a byte of free space back.

Edit: CCC keeps snapshots of your deleted stuff. Sigh.
Thanks DaisyDisk for sharing this:

CCC needs to change its name to ENF (Elephant Never Forgets).