I cleared my system to install the BigSur beta: enter image description here

So I have 62 GB free space.

But when Im in the installation process its shows the following:

enter image description here

Just 28 GB free space. How can I fix this?

when I look up my HDD via finder it shows me:

enter image description here

So that 34 GB should be purgable. But how to delete this stuff since my recycling bin is empty.

  • As this is a beta, you should report the issue to Apple.
    – benwiggy
    Jul 3, 2020 at 8:55
  • Its not a beta since im on catalina and was trying to install big sur.
    – gurehbgui
    Jul 3, 2020 at 10:43

3 Answers 3


I found a solution: I just created a new APFS parition and reserved as much space as possible. Then the space which was shown as purgeable was deleted automatically. After that i removed the partition again and had all the free space.

  • This would be super useful if you put in a screen shot or command how to do this, I think we’ll need quite a few threads like this to help everyone that’s not seeing APFS containers and purgeable space as something that can be managed / cajoled when needed rather than just letting the system prune things when storage pressure time arrives later. +1 even without extra details or an edit.
    – bmike
    Jul 3, 2020 at 11:01
  • Works perfectly in MacOS Catalina :-D. If anyone is interested here's a step by step tutorial: support.apple.com/en-gb/guide/disk-utility/dskua9e6a110/mac
    – Gajotres
    Sep 27, 2020 at 7:06

I think there is a problem with your startup drives... Just boot into Recovery Mode and run First Aid.

NOTE: First Aid will temporarily lock the startup volume.

  • This I also tired but it did not work.
    – gurehbgui
    Jul 3, 2020 at 10:43

Time machine local snapshots have been known to take up lots of purgeable disk space. Try entering this in Terminal.app

tmutil listlocalsnapshots /

if you see a list of things printed, those are likely using up your space. They are programmed to remove themsleves as your space fills up. Here is a thread with more info on this topic.

If you just want to remove them, you can run this command

for d in $(tmutil listlocalsnapshotdates | grep "-"); do sudo tmutil deletelocalsnapshots $d; done

and then after a few seconds go over to Disk Utility.

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