Unknown Space - Not System Restore Files

I've had this issue on every Windows 7 and onwards PC I've owned and it's the dreaded "unknown" space being used that gets bigger and bigger until it becomes noticeable. The issue is this time is it doesn't seem like the easy delete the system restore files option within Computer > System > System Protection



Here's the System Protection settings pages plus the command "VSSAdmin list shadowstorage" run as administrator which confirms no space is being used by shadow copies.



Something that is probably worth saying is that I recently moved from a HDD to a SSD by cloning the original HDD. Since then Programs and Features has not been displaying the file sizes of programs correctly with a number of them being exactly 6.51GB and others despite being 20+GB games (Project Cars) showing as having no file size at all!



This doesn't match the file sizes that Steam is reporting:



Anyone got any ideas on what this could be or a way of locating this unknown space?

Thanks.

Try running Treesize Free as administrator - perhaps that will help identify it.

lx07 said:

Try running Treesize Free as administrator - perhaps that will help identify it.

What do I look for in Treesize? I do have it already but it didn't seem to show anything useful from what I could tell.

crooky said:

What do I look for in Treesize? I do have it already but it didn't seem to show anything useful from what I could tell.

The unknown 54.4 GB I suppose. If the totals are the same in WinDirStat and TreeSize then that 54GB must be shown somewhere in TreeSize - from your first post perhaps games.

You could start with each top level directory (Program Files, Users, Windows etc) in both programs. Then compare the totals and drill down into directories where totals are different (assuming there are any).

lx07 said:

The unknown 54.4 GB I suppose. If the totals are the same in WinDirStat and TreeSize then that 54GB must be shown somewhere in TreeSize - from your first post perhaps games.

You could start with each top level directory (Program Files, Users, Windows etc) in both programs. Then compare the totals and drill down into directories where totals are different (assuming there are any).

Thanks very much. The issue was with the C:\Program Files\WindowsApps folder for some reason* I had lost permissions to it. It'd become read only, hidden and unable to be accessed until I added my account as an owner of the folder. After that I was able to have the permissions to access this folder again.

*Might have been some issue with uninstalling the Forza Horizon 3 demo
Here's a before and after on WinDirStat and Treesize

Before:



After:

crooky said:

The issue was with the C:\Program Files\WindowsApps folder for some reason* I had lost permissions to it...

You never had full control permissions for it. In a default clean install the owner should be TrustedInstaller and you should only have execute permissions.