What is eating up all that space in my Local Disk C? - 1

Windows itself is the likely culprit. Take a look at your Windows Restore settings.

Turn off windows update if your storage is becoming a problem. Windows updates itself regularly and takes data doing so

Program updates / OS updates / anti virus updates…
Temp folder…( have we ever cleaned that out? )
Recycle bin…( do we empty it? )
Lots an lots of things can eat up space…

See You Can Free Up Some Space By Deleting Temporary Files.

1. Goto Start -> Run -> Then Type "Temp"(Delete All Files From There. It Will Not Affect Your Computer At All.)
2 Goto Run Again Then Type Appdata Then GoTo Local And Then Goto Temp. There Also Delete All Files From There

I'm Sure It Will Free Up Much Space. See, Temp Are The Files Which Are Created During The Installtion Of Setup and Afterwards They Are Useless.