Recently I reinstalled my PC and installed Windows Vista on it. After using it for a month, I noticed that the free disk space was becoming very limited. In explorer the disk property showed me that I used 46GB but when I selected all my folders and retrieved the size, it was only 21GB.
So where did that 25GB go? Aparently it is the system restore utility (which uses shadow copies) that is happily using my free disk space. Especially on a laptop with limited disk space this is not funny. Opposed to Windows XP, Vista doesn't provide a graphical utility to manage the system restore memory settings. Although, there is a way to change these settings.
If you open a command prompt and type vssadmin list shadowstorage, you can see the used space.
To change the settings, you need to use the vssadmin resize shadowstorage /for=[disk_drive]: /on=[disk_drive]: /maxsize=[max_size]. The sample below sets these settings on my machine to a maximum of 1GB:
vssadmin resize shadowstorage /for=c: /on=c: /maxsize=1GB