I am on Mac OSX 12.3.1. I wanted to upgrade from Cubase 11 pro to 12 pro.
Is your USB-eLicenser plugged in and recognized by the eLCC with the Cubase Pro 11 license?
Not many details in your post to help solve the problem.
Do I have to plug in USB-eL to upgrate to cubase 12Pro from Cubase 11Pro?
Why they always make the process so compilicated!
Yes, that is needed because your Cubase 11 license is on the eLicenser and needs to be verified for upgrade.
What is complicated here, if you just need to keep the eLicenser connected for a while?
Thank you.
Unfortunately, I left my USB eLicencer far away being assured that do not need it anymore. Steinberg has already all my licenses including Cubase 11Pro. Everything goes through the registration process on line.
Thanx and have a great day 
Yeah, after upgrading.
The USB-eLicenser dongle is required to verify that you still have a Cubase Pro 11 license to upgrade. Steinberg can’t know if you still have the dongle with the previous license in it otherwise.
If you wont have access to your USB-eLicenser for a few months, you can order a new dongle and request Steinberg Zero Downtime: