A verification operating system (VOS) is an intermediary operating system that verifies data of a primary operating system before the primary operating system controls of the computing device. When the computing device is initialized, initial boot processes load the VOS instead of the primary operating system. The VOS performs verification processes on data storing the primary operating system to verify that the primary operating system has not been manipulated or corrupted before passing control of the computing device to the primary operating system. A VOS also may be used to verify an operating system used by a virtual machine (VM). The VOS verifies data storing a VM operating system to be used for requested VMs. If the VOS verifies that the VM OS data is accurate, the VOS provides the VM OS data to a hypervisor for use in a VM.