Purgeable taking a lot of space from my hard disk
I have Macbook pro, I tried to back up my I phon X max to this matchbook but it stated I "the mac book doesn't have enough space for the backup) while my hard disk size is 750GB, and I have 480GB purgeable, in which it's under the available space, when I check the storage it stated 515GB available, what should I do the clear the so called "Purgeable" and gain bace my the empty space on my hard disk???
Note: my phone That I want to do backup for it used 220GB of it's storage.