system installation - Error Code after trying to instal your Ubuntu Desktop Download on VirtualBox for MAC

As i said in the object, I cannot install the your Ubuntu Desktop ISO Download file on VirtualBox with MAC.
I created the new environment to setup the Linux operating system on VirtualBox with normal specs (1024 Mo ; 10 GB ; Dinamic Disks ; ..) but when I try to run this new environment for the first time to put the Ubuntu ISO inside i get this error message :

NS_ERROR_FAILURE (0x80004005)

MediumWrap
IMedium {ad47ad09-787b-44ab-b343-a082a3f2dfb1}
IVirtualBox {d0a0163f-e254-4e5b-a1f2-011cf991c38d}
VBOX_E_OBJECT_NOT_FOUND (0x80BB0001)

Can you please help me to solve this problem?
Thanks for your help i'm learning but already stuck !

Franckay