After a day of testing I was able to upload free from Cubase Artist 11 (State of Grace) to Cubase Artist 12 by manually launching the SteinbergActivationManager.exe file present in the Directory Program >Steinberg >Activation Manager , because the app Steinberg Download Assistant has a bug.
I advise everyone not to load Cubase Pro 12 Trial because this software (like Cubase Pro 11 Trial ) does not allow you to save Audio files, as the window that appears by selecting File> Export> Audio Mixdown is partial and do not appear the tabs at the bottom needed to save.
With Cubase Artist 11à
File >Export> Mixdown Audio all is
OK 
I have found that the reason for the incomplete Mixdown Audio window to occur is that Cubase Pro 12 (and Cubase Pro 11) want a resolution greater than the 1440x900 stated in the Steinberg specification. 
Hi,
Please follow the minimum system requirements.
You can export Audio in Cubase 12 Trial the very same way, you can do with the retail license.
It would be nice to update your description.
Sorry, I may not have understood correctly: I found that to save Audio Mixdown for Cubase Artist 11 or Cubase Artist 12 a resolution of 1440x900 is sufficient as indicated in the Steinberg specifications. For Cubase Pro 12 Trial (as with Cubase Pro 11 Trial) this is not enough because a resolution of 1920x1080 is required.
You can do some tests by decreasing the resolution of the PC (Windows 10) to 1440x900 or 1600x900 to verify, as I did.
Maybe you mean that a resolution of 1440x900 is enough for the paid version of Cubase Pro 12?
Hi,
I’m not on Windows, but I know this issue. If you are using the minimal resolution (1440x900) you have to hide the Start/Task bar. Otherwise this will steel some pixels, you need in Cubase.
I had already done that. Moving the taskbar to the right, which by default is at the bottom, you can recover about 100 pixels of Vertical resolution. But for Cubase Pro 12 you need a lot more pixels 1980x1080. Thanks anyway for the tip.
I do not recommend loading Cubase Pro 12 Trial to those who do not have a PC with a resolution of 1980x1080, because they risk not being able to use it and only waste time. Vice versa, I highly recommend it for those who have such a resolution.
Thank you very much for your interest in the problem.
