I saw your link in the Acronis Forum.
Does Acronis affect Volume Shadow Copy service?
http://forum.acronis.com/forum/51995
Windows 8.1 built-in System Image programs are useful to know about.
How to create a system image to refresh your Windows 8 PC
http://support.microsoft.com/kb/2748351
How to create a custom refresh image in Windows 8
http://www.bleepingcomputer.com/tutorials/create-custom-refresh-image-in-windows-8/
Just because you have only one user does not prevent you from creating a second user should you need to.
Create a user account Windows 8.1
http://windows.microsoft.com/en-au/windows/create-user-account#create-user-account=windows-8
It may be possible to Audit access to files that vanish in mysterious circumstances.
Auditing Access to Files
http://www.gregthatcher.com/Papers/IT/audit.aspx
I realize that later posts indicate that your problem may have been resolved, I hope so. I would also like to add that the use of Registry Cleaners and their like often cause weird and wonderful errors and should be avoided like the plague.
MVP
According to Microsoft, Microsoft Most Valuable Professional award is given to "exceptional, independent community leaders who share their passion, technical expertise, and real-world knowledge of Microsoft products with others."