141gb System size, is there any way to find where all that clutter is coming from?
You should get a utility like Daisy Disk or Grand Perspective which will make a visual mapping of your disk drive so you can see what is taking up so much space. DaisyDisk is $10 but has a free trial period so you could use it to check your disk. Grand Perspective is Free.

You may want to check your Library folder as well. It can get quite big. I don't know if the Library folder is part of system. You have 2 library folders on your system. Be sure to check the one in your home directory.