How to convert .img to usable VirtualBox format

1. Select a virtual machine by clicking its name in the VirtualBox window
2. Click the Machine menu at the top of the VirtualBox window, and click Settings
3. Click the Storage category in the Settings window
4. Right-click in the storage tree pane, and click Add Floppy Controller
5. Right-click the Floppy Controller device, and click Add Floppy Device
6. Click the Choose Disk button in the prompt window that appears
7. Navigate to the floppy disk image file (.IMG) on your computer and double-click it

If that doesn't work, try renaming the .IMG as .ISO and mount it.

If that too doesn't work, use VBoxManage's convertfromraw command as follows:

VBoxManage convertfromraw --format VDI [filename].img [filename].vdi

Mount the VDI as a hard disk.

Windows 10 can mount .img files as a drive. This drive can then be accessed by a virtual machine.

1. In Windows Explorer, right click on the .img file, select Mount.
2. Start the virtual machine
3. In the Devices menu => Optical Drives => select the Host Drive created in step 1.