This pop up "Signed out of Lightroom mobile" is showing up because by default Lightroom mobile is selected in Identity plate.
Now as your trial has expired and you are no longer signed in .It is showing current status of Lightroom mobile
To remove this from Identity plate please Right Click on Identity Plate and select "Lightroom"
Restart Lightroom once done
Let us know if that helps
Well, I am using a custom identity plate but I tried your suggestion and it didn't help. What would help is if Adobe didn't automatically do anything I didn't want them to do like sign me up for Creative Cloud (free membership or not) and change my application settings. Perhaps Adobe thinks that eventually, if they pester me enough, I will sign up. Not likely. The more I get pestered the more likely I am to run in the other direction.
I too am tired of being pestered by this. I don't use mobile and therefore don't want to log in to sync.
I found the option as you showed and unchecked "Sync with Lightroom mobile" but it still gave me the same pester box when I started up again.
This is really annoying!!!
Did you also stopped synced from the Identity plate?
I actually found the answer in another message here.
I had to make sure sync was turned out
log out (Help -> log out)
This causes you to have to log on and reenter your license key.
So far, no more nag screen
I tried to turn sync off and I did (Don't know exactly how I did it bur it turned off the notice and I am in business again Thanks a lot for your help.
Was annoyed to heck with this issue and stumbled on your answer. Just tried it and am crossing fingers that it works as advertised. Thanks for sharing!