QCOW2 is the file extension that is specific to a system emulation and virtualization program called QEMU. QCOW2 is one of the file formats that QEMU uses to store disk images. These files are characterized by the fact that they additionally support AES encryption and zlib compression. These files most often contain data on the virtual machine's hard disk.

QCOW2 files are successors to QCOW files, though these are still supported by QUEMU.