Yes it is activated. Just to confirm I opened another empty proj and it came up not activated.
Just to reiterate a “clue” - All this started immediately after I enabled Cue 1 and a track that used a Cue Send
Back to the active project:
Can you click the global Mute button two times, please. Does that change anything for the playback activity?
Interesting. Still no audio but now the playback cursor does not move although the Primary Time Display does change normally
But inside the wav editor the cursor and audio work normally
Thanks. It’s deactivated. Several posts suggested just restarting Cubase to “fix” this issue. Restarted fresh in safe mode, cursor moves normally again but same no-audio issue
Just fishing for ideas: can you try to download and (re)install the latest driver for your Scarlet audiointerface here (make surd to pick the correct gen, please):
Maybe your ASIO driver is outdated or corrupted, these things can happen. After installing the driver, please restart your system and try to launch Cubase in safe mode, first.
Does any track with solo enabled play back?
Thanks and great idea, my Scarlett Solo has very old fw and drivers. I’ll install first thing tomorrow AM and run the test (late here now 
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Not so far. Will try tomorrow with new audio I/F sw.
Great news, Reco and Johnny. Reco, your suggestion to update the (old) driver for the Scarlett Solo audio interface 100% fixed the no-play-audio issue and now the Control Room Cue A/B compare track thing works fine. I first started in safe mode, then started normally with simple and then more complex projects. All work now.
A couple of things: 1-the (Windows) Focusrite Control app is supposed to flag newer software if it’s available, it never did. 2- my net conclusion is that when I first activated the Cue feature in Control Room that appears to have caused Cubase12 to require the audio driver to do something differently. Whatever it was the change “stuck” until the driver was updated.
Thanks again (!) Reco and Johnny for your time helping with this.