I too have Windows 2012 Essentials eating up hard disk.
Yes, I tried chkdsk.
Yes I have tried optimization.

I too, installed WinDir ....    Unfortunately, in this case...  it has found 70-GB of something it can't identify either.  On a C:\  partition of 80GB, it was horrific.

Just a large "blob" ... is can't identify.. and has no extensions assigned to it either.   I am at loss as to where to go.
This is a small server.. and is not really connected to anything but the Internet (yes firewalls are up.)

I finally had to use a third party tool to increase the space. Now at 100GB, and whatever it is, is still consuming about  880MB per day.

Any help or suggestions would be greatly appreciated.

• Edited by Merle Wait 13 hours 29 minutes ago

Hi Merle:

Did you right click and "run as administrator" when you ran Windirstat?

Was the unknown space consumer on the root of the partition or in a folder?  If in a folder what one?

Yes, I did Right Click - Run As Admin.

It is is the "root" c:\     - nothing but I big blob
http://ebt.net/images/thelargeblob.jpg