The strangest thing happened. I updated to 4.1 then clicked my Dorico 4 icon to open and Dorico SE 4 opened instead. I’ve never used SE so I was confused. It has a white start up screen. The start up window has a red “upgrade” button. I closed it and clicked the icon again and this time it opened Dorico 4 like normal. Is this some weird registration bug? Anyone else experience this? It seems to be working fine now, but man did it freak me out 
You were not accidentally leaning on the CTRL or ALT key (or their Mac equivalents) were you? Those modifier keys (and I can never keep them straight) allow Dorico Pro to open as Elements or SE.
(A temporarily stuck key might do the same.)
Hmm. I didn’t think so. Maybe I was? I had no idea that was a thing!
Ok, so I tried this and it opened Elements. There is a slightly gray startup screen. There is not red “upgrade” button. This is not the same thing that happened. Is there another key I can hold down to make it “Dorico SE 4” rather than “Dorico Elements 4”?
Hold the Alt key while starting Dorico to launch Dorico Elements, and hold Command (Mac) or Ctrl (Windows) to launch Dorico SE.
Holding Alt opens Dorico as Elements, Ctrl as SE.
Ninja’d…
It might be me that has them the wrong way round, of course…
I had it the other way but doubted myself…
ahhhhhhhh I have to hold down opt+cmd on Mac to get it to open SE. GOD I was freaked out by that. Interesting feature. Thanks for letting me know!
Is there any known condition other than the keypresses that causes Dorico PRO to open as SE? It happened to me today (and I’m as certain as one can reasonably be that I didn’t have any fingers on those keys), I didn’t notice for a while, and its refusal to save my orchestral project freaked me out for a while, until I restarted everything and finally noticed the startup screen. I had to quit and relaunch Dorico a couple more times before it launched as Pro. All good now, but it would be useful to know how I made it happen, if it was indeed something I did.
Do you have both a Dorico SE and a Dorico Pro license showing and activated in Steinberg Activation Manager? If so, I would advise deactivating Dorico SE.
No, there’s no Dorico SE license in the Steinberg Activation Manager. (I checked so as to give a responsible answer, but in fact I’ve never had an SE license – I’ve been a Dorico Pro user from the day it was released.)
I can remember this happening one other time, maybe 4 or 5 months ago. In both cases it was relatively short-lived; one or two quits + relaunches restored me to Dorico Pro, once I realized what had happened.
My colleagues who are working on Steinberg Licensing might be interested to see the logs to see if anything obvious can be gleaned from them. Please do Help > Create Diagnostic Report in Dorico and attach the resulting zip file here, and I’ll ask them to take a look at it.