Double click on your HD icon. I have: Applications, Incompatible Software, Library, System, Users. (All files.)
Then click on your Home icon (your username/log in name). I have: Desktop, Documents, Downloads, Dropbox, Incompatible Software, Movies, Music, Pictures, Public, Sites.
I deleted the contents of both those files and emptied the Trash.
The Read Me file in the Incompatible Software folders says:
"
Incompatible software
Some of the software on your computer is incompatible with this version of Mac OS X. Because this software may cause problems with your computer, it has been moved. You can delete incompatible software that was moved.
Incompatible software in your home folder was moved to a folder named "Incompatible Software" in your home folder: [List of software."