"System" storage on macOS Sierra is 470GB! My Mid 2012 MacBook Pro 13" says I suddenly ran out of Storage space. 

My Mac barely has any data and my upgrade to Sierra was a clean install. Nothing was ported from previous backups. 

If you see the image below, the "System" section in the left column says that it is consuming 466.82 GB. What I don't understand is why does my Mac require so much space? As far as I know, it should never increase 50 GB of space. Any help is appreciated.
Download OmniDiskSweeper and analyze your hard drive.


  OmniDiskSweeper will show you the files on your drive, in descending
  order by size, and letting you decide what to do with them. Delete
  away, but exercise caution.
  
  


OmniDiskSweeper will show detail of space usage: 
Select System and start cleaning.

It could be the Time Machine backup file that takes almost all the free space.