> CCleaner is still popular... which is quite ironic as it damages the Windows Registry
CCleaner has two main use-cases: a performance tool (allegedly) and a privacy tool.
You assume that CCleaner is popular because people think that it boosts performance. This was never my use-case and anyone that I've seen actually uses it as a privacy tool, i.e., to clean up browser history, delete caches, wipe free space, etc., to not expose what they've been looking at, searching for, and downloading.
With respect to privacy, if I see someone using CCleaner, I recommend that they switch over to BleachBit[1] which is open source and which even Bruce Schneier swears by. I used both simultaneously for awhile on my Windows systems and found that BleachBit found many more privacy-sensitive files to erase than CCleaner.
If you're interested in privacy and have Windows 8 Pro, you can use Client Hyper-V and Differencing Disks to make what is effectively a "read only" system. You boot into the VM, do whatever it is you have to do, then shred the differential [0].
Alternatively just encrypt the VM[1].
Alternatively again just run a Linux "Live OS" from a DVD and pull the power to "wipe."
Alternatively ad-infinitum make a Windows To Go Thumb Drive and smash it with a brick when you're done.
CCleaner has two main use-cases: a performance tool (allegedly) and a privacy tool.
You assume that CCleaner is popular because people think that it boosts performance. This was never my use-case and anyone that I've seen actually uses it as a privacy tool, i.e., to clean up browser history, delete caches, wipe free space, etc., to not expose what they've been looking at, searching for, and downloading.
With respect to privacy, if I see someone using CCleaner, I recommend that they switch over to BleachBit[1] which is open source and which even Bruce Schneier swears by. I used both simultaneously for awhile on my Windows systems and found that BleachBit found many more privacy-sensitive files to erase than CCleaner.
[1] http://bleachbit.sourceforge.net/