Windows 7: unknown file using a lot of space

according to WinDirStat there is an unknown file using 21% of my "C" drive. how can i find out what it is, so that i might be able to clean it up?

It may be temp folder . Press Win +R simultaneously to open the run box , and type %temp% in it and hit enter ... you would be able to see the temp folder .

In WinDirStat click on the large file and it will tell you were it is. -WS

checked temp file, it only totaled about 10mb. i have run windows disk cleanup but it did not include this unknown file. in WinDirStat the file is the next file under free space and like free space it is blacked out. it is using 194gb. my total usage out of 920gb is 329gb. of the 329gb i know what 135gb is being used for because i have a lot of video and music files. WinDirStat will not let me open it up. i am attaching a snippet of the WinDirStat window.

I just ran WinDirStat...

When you click on an object in the file tree in the left column, the program automatically highlights the file type in the right column. According to your screenshot, the file that appears as "Unknown" on the right side is highlighted as "VLC Media File (AVI)" on the right side.

Do you in fact have a rather large .avi file residing on your drive?

yes all of my video file are .avi. but, when i check properties for the video folder it says i am only using 92gb. maybe i am not understanding. is the VLC video file separate from from the video files? could it be that it has copies of the video files plus any meta data? i am not really all that familar with VLC and what it does. i basic use it because it can transcode videos on the fly.

So, you have your video files in their own folder?

In WinDirStat, when you right click the unknown file and select properties, where does the dialog box state that the file is located?

Also, on the status bar at the bottom of WinDirStat, it should show you the file path when you select a file from the left column. I don't see that on your screenshot.

Opps, too many software options in my head. I meant: Right Click on the picture and "Explorer here.." the software will jump right to the file.

i have taken another snippet of WinDirSat with only only the unknown file highlighted and with the treemap option on. where do i go from here?

From the looks of your latest screenshot, it looks like the file is in C:\. Besides the normal folders Windows installs to C:\, do you have any other files there?