WinError

WinError is a tiny and portable application that displays fake error notifications on the screen. It can be seen as a prank.
It may look like a useless app, but it actually comes in handy whenever you want to "protect" your files from unauthorized users who might look into your private information.
As installation is not a requirement, you can drop the executable file somewhere on the hard disk. Error messages will pop up with every access of the file (multiple instances are allowed).
With every new instance, the title bar has a different error name, such as "Default IME" and "NvSvc, " along with names relevant to active windows.
Clicking on the "Details" button brings up an additional panel with a message and "Abort," "Retry" and "Whatever" buttons. Unfortunately, you cannot customize this text.
Errors will keep popping up until you terminate WinError's process from Task Manager. Note that no real damage is done to the system.
There is also the possibility to save WinError to a USB flash disk or similar storage unit to trick other people into accessing it, thinking they will find personal data (you can make the real files hidden, for instance).
What is worth mentioning is the fact that WinError does not add new keys to the Windows Registry, or create extra files on the hard disk, leaving it clean after removal.
The tool does not put a strain on system performance, since it runs on a very low amount of CPU and RAM. It has a good response time and, although it has not been updated for a while, it works smoothly on newer operating systems.
WinError is a fun tool whenever you want to pull a prank on your friends, especially the ones who are usually nosy about your computer files.