macOS Catalina – How to Clear Disk Space

If you are saying you have 1GB of free memory then the problem is not what is grabbing that 1GB but the lack of memory in the first place.

This will get worse overtime because you are already hitting 0 bytes and operating system needs space to write out its files.

I strongly suggest you move essential files like photos a video media off to an external drive to free up some memory. These type of files being normally the largest and easiest to move. ( Do not delete any system files unless you know exactly what they are and removing them will not break you system)

Try and give yourself at least 10-15% free space as a minimum and keep at or above that.

I would try the following since all basic configs/lists/outputs look fine:

• boot to Single User Mode
• /sbin/fsck -fy

• Display free disk space /bin/df

  Example:

  Filesystem  512-blocks        Used  Available Capacity   iused     ifree %iused  Mounted on
  /dev/disk2  6066780416  5644868776  421399640    94% 705672595  52674955   93%   /
  

  Here 94% of the disk space and 93% of the inodes are used.

• If free disk space ~0 /sbin/mount -uw /

• Change directory cd /Users/user_name/path/to/big/file and list files with ls
• Print working directory to be sure pwd
• rm big_file
• Display free disk space again /bin/df
• boot to main volume with exit

You may have to remove some really small files (size < 100 kb) first before you succeed deleting the big file.

If this fails get an external disk, partition and format it (JHFS+) it in Recovery Mode or with a second Mac. Attach it to the broken Mac, boot to single user mode (cmdS while booting), mount the external drive and rsync your user folder and other important files & folders to the external volume. Then erase Macintosh HD and reinstall OS X. You may also rsync your complete system!

Mounting an external drive to /Volumes (even though the boot drive is readable only) should be possible by using:

gpt -r show disk0/1/2 #search for the proper drive because *diskutil* won't work in SU mode
/sbin/mount_hfs -o nosuid -w /dev/disk2s2 /Volumes/ #mount the external drive (e.g. disk2s2) to /Volumes
rsync -aAvX /Users/user_name/ /Volumes/user_name #Backing up the user folder. 

If the above rsync options don't work use something like rsync -aE ... instead.

The root of the external drive is directly in /Volumes (so no volume name in-between like on a normal system: /Volumes/Volume_name_ext_drive/).

After rsync'ing check the content of the "new" user folder.

(Tested in a VM)