Sandboxie is a general-purpose computer security software that runs your programs in an isolated place that stops them from doing permanent modifications to other programs and data in your computer. Sandboxie grew out of its creator’s experience of being infected by malware that caused unchangeable damage. If a program in the sandbox attempts to open a file with write permissions, Sandboxie transparently copies the file into a sandbox and redirects all access to that copy rather than the original file on the system.
That idea is extended to all parts of the system, e.g., the registry. The program attempting to make the modifications perceives that it was successful, it doesn’t know that it made modifications to a simulated copy.
Sandboxie creates a fork of the real system to create an isolated view for programs that run inside the sandbox. Using Sandboxie is a better solution to malware protection than browsing through a virtual machine (VM) due to not having to install a new OS, a new set of applications, and maintain both your primary machine and a secondary virtual machine.
Using a separate Virtual Machine makes it hard to move files between your main system and the VM and needs a dedicated amount of RAM from your system. Sandboxie is transparent, and most of the common usability problems have already been addressed.