Feb 21, 2014 How to find and delete large files / folders on your Mac OS X hard drive running Mavericks. This is a great way to quickly free up hard drive space on your Mac computer. More Mac OS X tutorials. Apr 28, 2016 What the “Erase Free Space” feature did (and still does in prior versions of Mac OS X) was overwrite the free space on a drive to prevent file recovery, adding a layer of security and privacy to file removal, much in the way that Secure Empty Trash performed a. How to check a Mac’s free hard drive space. Even the largest drives fill up eventually. Click the Storage tab in the toolbar to see how much disk space you have available.
Will the computer get past the blank screen if you try SafeBoot mode where you hold the shift key down through startup? If successful, you'd probably have to also log in to the admin account. Then the computer could operate with a reduced system, and that means volume won't work, internet won't work and other stuff is off.
Can you boot into a recovery partition, if the installed system is OS X 10.7.5 or later? If not, does the computer have an optical drive and do you have an install DVD for the current system if 10.6 or before?
How did you use Disk Utility to 'repair disk permissions' ? If booted from a Recovery partition and OS X Utilities, that method offers 'repair disk' too.
There is a chance the hard disk drive has failed, and if you had a replacement drive of correct specs, plus an external enclosure for the one in your computer to be put in later, at a later time you could attempt to access the Mac's drive to reclaim any libraries or otherwise lost content.
There are kits one can buy, such as one from OWC macsales online that can include a replacement HDD and an enclosure; so it is possible to prepare the new drive for use in the Mac, or swap drives; and end up with the old one inside the enclosure where you can attempt to access content later, or migrate some back in.
Since there are several unknowns about your model MacBook that affect advice, the blanket article on this topic starts with Support...
•Mac OS X: Gray screen appears during startup
A new installation creates a new system folder, adding to the overall situation of insufficient capacity in the computer's hard disk drive. If you have libraries of iTunes, iPhoto, iMovie, and saved video, etc you may have to see about getting an external drive (USB) and learn how to move libraries into the external so you can later access them from the computer's applications that use them, then delete the ones inside the computer. Or get the stuff to replace the internal HDD, and put the original HDD inside an enclosure for later migration.
Free Disk Space Mac
There is a lot unknown, so if SafeBoot can help get into the computer, that may be a start. To get in.
How Much Hard Drive Space
If the computer happens to be a model with FireWire ports, and your second Mac computer has them also, then you could start the troublesome one in Target Disk Mode so it appears to the healthy one as an external HDD. You then could attempt to repair the failing MacBook's HDD and also attempt to remove your wanted files. Drag and drop is not a good way, but you should have a backup system in place, where copies are correctly made; or where you have a backup clone (it can boot the computer from external self-powered HDD) for emergency.
Clear Up Disk Space Mac
At least you have a second computer & internet...
Free Up Space On Mac
Good luck & happy computing! 🙂