This is a recent situation I've been having since the last update to Lightroom Classic, maybe for the last week or so. Every time I startup Lr Classic, I have to manually login on creative cloud via the "Get started with Lightroom CC" button in the upper left corner. I'm already logged in on the creative cloud desktop app and that stays logged in without incident. Everything else is functioning well, it's just having to sign in every time that is an issue. Has anyone else had this recently and been able to resolve?
I've been having this problem and just posted my own as I didn't see yours right away. For me, I found I was not logged into the created cloud desktop app, so I signed in there. Next I started LR and this time LR is signed in to sync. So my assumption is the desktop CC app needs to be signed in.
If you hadn't sign out of both. Quit LR, sign in to the Creative Cloud desktop and then start LR again. Still not signed in in LR?
Making sure I was logged into Creative Cloud Worked for me ... thanks