Q: Why is my disk full and how can I clean it up?

How to Free Up Space on The Hard Drive

1. You can remove data from your Home folder except for the /Home/Library/ folder.
2. Visit The XLab FAQs and read the FAQ on freeing up space on your hard drive.
3. Also see Freeing space on your Mac OS X startup disk.
4. See Where did my Disk Space go?.
5. Be sure to Empty the Trash to recover the space.
6. Replace the drive with a larger one. Check out OWC for drives, tutorials, and toolkits.
7. Use OmniDiskSweeper 1.8 or GrandPerspective to search your drive for large files and where they are located.

That display often does not accurately represent the data on the disk.  Often, but not always, a Spotlight reindex will correct the problem:

https://support.apple.com/en-us/HT201716

Ciao.

You are looking at the WRONG thing. You are clicking on the physical drive (see the top picture below). That ALWAYS shows a full bar because you have the entire drive partitioned and formatted for use. If you want to see the actual space used on your hard drive, you need to click on the partition (see second picture below).