Why Disk Utility full? My Disk Utility is full. My Disk is about 1T but now I only have no more 100GB to use.
 I don't think I have used that much, the yellow one is belong to what? I want to erase some files to get more spaces but I have no idea what to do.
I think all of my folder is just 400GB. I think either Application or images, video are duplicate in somewhere. Please help!!
Open finder and use the go menu to open your home folder. 


press command 2 to get the folder list view
press command j and turn on Calculate all sizes 


Once you know how large these folders are, you can start determining where the "other space" is allocated. I like to sort by size, decreasing so that the biggest users of space bubble up to the top of the window.