YOU CAN USE SOME APPS, BUT REMEMBER, DELETE FILES THAT YOU DON’T USE AND MAKE SURE USE A CACHE CLEANER:
If, for any reason, your startup disk becomes completely full, your Mac may fail to boot or simply start the boot process and then shut down.
The steps to follow involve using Single-User Mode. This startup mode only loads the system kernel, and you will be presented with the command line. Don’t worry, as the steps are straightforward.
Let’s go step by step:
Press the power button on your Mac.
Immediately press the keyboard shortcut ⌘S.
Allow the startup process to complete. When finished, you will be left with the command line interface. Ensure that you are in root mode, as any mistakes can be catastrophic.
First, we’ll mount the startup hard drive in read-write mode using the command mount -uw /. Keep in mind that when starting in single-user mode, the keyboard layout is American, so the hyphen symbol will be on the key with a single quote (‘).
Now, let’s delete the user cache folder. This folder is unnecessary and can take up several gigabytes of space, the space needed to free up for the disk to function properly.
We’ll delete that folder with the command: rm -rfv /Users/username/Library/Caches
Replace “username” with the actual username for which you want to delete the cache.
The deletion of files will now begin, and it may take some time depending on the quantity and disk speed.
Once it’s done, it’s time to reboot with shutdown -r now.
The Mac will start normally, but you haven’t completely solved the problem. You’ve only made some space for it to boot, and you’ll need to free up more space on the disk by deleting or moving files, leaving at least 30% of the disk free.