If you are using a Linux OS as a host, open the terminal. For Windows systems, open the command prompt and type the following command: VBoxManage modifyhd windows10.vdi –resize 30000Copy Where windows10.vdi is the name of your virtual disk and its full path, and 30000 is the amount of space the size of which you’d like to change. Press Enter. When the progress bar reaches 100%, the edit size operation is complete.