Failed to open a session for the virtual machine Ubuntu.
Call to VidMessageSlotMap failed: Last=0xc000000d/87 (VERR_NEM_VM_CREATE_FAILED
).
Result Code: E_FAIL (0x80004005)
Component: ConsoleWrap
Interface: IConsole {872da645-4a9b-1727-bee2-5
585105b9ee
d}
VBOX.LOG
See here: https://www.virtualbox.org/ticket/18536