Interesting, so if I never did anything to keep it 'clean' like a backup or something, can I still switch back to the sysNAND and play online even if I have Atmosphere installed? I understand that I should only launch official games when on sysNAND
I have exactly the same issue. Updated with ChoixDuJour from 8.x to 9.2 with the latest Athmosphere. Rebooted and got that error. Deleted everything inside the theme folder and any nxtheme that I could find anywhere else + copied again all the athmosphere and payload files.
Still the same issue...