Originally Posted by whrcville

Windows reports only 17GB free out of 141GB available on my C drive. But I'm only using about 50GB, so I'm missing about 74GB, or more than half my disk. When I run a program called WinDirStat, it reports 74GB as "unknown." Can anyone tell me what has happened to this space and how I can get it back?

Bill

You are missing only 50Gb or so from what I can gleam from the limited info you have provided. (i.e., 141GB total HDD storage-50GB used?-21GB Shadow Copy storage-17GB free= 52-53GB (approx) unaccounted for storage on the HDD)
Do you have Movies/Videos on your computer? These take up a huge amount of storage (as do Installed games).

This could not be accounted for with Shadow Copy storage, If Windows see the entire 141GB HDD. Only 21GB or so is available for Shadow Copy on your system (15%). If your lucky this will enable you to restore Windows/files/folders back a few days. That still would only account for approx. 71-72GB of your HDD though.

Shadow copy is what enables you to perform System restores, and the ability to restore deleted/changed files/folders to a previous point in time.
When you state you are only using about 50GB, where do you get this number from? Your Vista Windows Install and all installed programs, downloads, Music, Installed Games, Videos (these take up alot of storage (approx 1GB per video/movie), etc?

So the question here is where is the missing 54GB of Disk storage? Do you have a partitioned drive? and what have you installed, and what does Disk Managment report?



note- 150GB HDD is very small and will fill up fast in Vista. I suggest you use the Vista backup Imaging utility, and upgrade your HDD, and then after re-imaging, extending the volume size to span the entire HDD. you can get 320GB-1TB HDD's from $40-$100 or so.

Check the Volume in Disk Management, then post a screen shot in your post:

To access Manage utility:
start>in search bar, type,manage>click "computer management">click "continue">click "Storage-Disk Management"

Here is disk management

As you can see i only have a single partition on my drives. Snip and attach an image ot yours so I can look at it.
http://www.vistax64.com/tutorials/148532-how-use-snipping-tool-vista.html


note- If you click the below image it will enlarge for better viewing: