Zorin 17.3 Pro Upgrade (From 16.3 Pro) Borked

Installing Zorin OS
12

It checks the checksum of the installation file.
Question: Did you manually check the SHA256 checksum of the ZorinOS 17.3 downloaded .iso file, before trying to burn it to USB? see this: Methods of downloading Zorin OS - #8 by zabadabadoo

and/or,