Also, don't forget to run windirstat as an administrator. There will be less unknowns that way. 
I'm having issues with unknown files taking up storage on my C drive which has happened many times before this. Tech Support had me download WinDirStat to identify these hidden storage takers and delete them.  When I run WinDirStat now the files show up as and will not even let me see the properties let alone delete them out of storage.  Currently taking up 182gb and counting after every restart.  There is also a doing the same thing but at a smaller capacity.  Also having issues with SupportAssist failing to complete updates. Tech support corrected the problem yesterday but now with booting up today AWCC ( Alienware Command Center) will no longer work. It will try to launch and then automatically closes out. I switched the properties to automatic on start up but did not help. Any thoughts would be greatly appreciated.  Thanks 
Aurora R9, issues with storage and ACC