I can't get Parallels to create a macOS 13 beta VM. I have downloaded the required ipsw file and tried to create a VM manually using the command line. After typing the command (as advised here: https://kb.parallels.com/125561/), I got a dialog saying a software update had to be downloaded. After 30 seconds or so of no activity I got a dialog advising that the software "is not currently available from the Software Update server". I checked my LittleSnitch settings in case that was a problem but, they were fine. I tried the command again and nothing happened. I closed, then reopened Terminal and tried again. Nothing happened. I mean that literally: no response in Terminal; and no network accesses. Does anyone know what software update would be needed and how to get it ? Thanks.