What causes the "Failed to create the hard disk storage" error when creating a new virtual machine?

This is the error I received:

Failed to create the hard disk storage C:\Users\Sara\VirtualBox VMs\OSOS\OSOS.vhd.

Could not create the medium storage unit 'C:\Users\Sara\VirtualBox VMs\OSOS\OSOS.vhd'.

VHD: cannot set the file size for 'C:\Users\Sara\VirtualBox VMs\OSOS\OSOS.vhd' (VERR_DISK_FULL).

Result Code: VBOX_E_FILE_ERROR (0x80BB0004) Component: Medium Interface: IMedium {53f9cc0c-e0fd-40a5-a404-a7a5272082cd}


The error code VERR_DISK_FULL sums it up. Your disk is full. Free up some space and it should work.