[Solved] How to fix VirtualBox - /sbin/mount.vboxsf: mounting failed with the error: Protocol error

Virtual box is a great tool for Java developer to run Docker and Linux on Windows Machine, especiall for them who need to develop and debug Java program in Linux environment. I use Oracle's virtual machine, VirtualBox to run the Linux operating system from my Windows machine. It's the most simple way to have two operating systems on your laptop or PC. Since I run most of the Java programs in Linux, VirtualBox gives me a nice interface to run UNIX commands right from the Windows box. This blog post is about the mounting of a shared folder failed error in Oracle's Virtualbox VM. It was working fine the day before yesterday and now, after I restarted my virtual box and tried to mount my shared folder, I was greeted by this error: "/sbin/mount.vboxsf: mounting failed with the error: Protocol error".