System data taking up nearly 80% of HD
Why is System data taking up 80% of HD?
And how do I delete it?
The main Culprit in your above image is the System Data category >> 190.25 GB
That would be the Home Folder of each of the User Accounts used on this computer
We arrive at this by the Other Users & Sharing category >> 292.5 MB
If you are the Owner and Administrator of this computer, suggest dealing with them and have them to off load some of the Applications, Videos, Music, Photos and Games
If Only one account on the computer, review what is being Shared