@Artoforian, @karim @anybody else with this problem,…
Please be advised that if you follow Karims well meant advise,in terms of deleting the graphene folder and install new, that you will loose all your customization for your theme, IF you don’t have a Child theme installed as the customizations are saved in the style.css.
Here is another option which works. In case you have done after finishing your customization of the me and “Export” of the “Graphene Theme Options”, you can do as Karim described, by deleting and reinstalling and then importing your “theme options again. Works too.
I run Graphene Theme on many of my clients websites and like it a lot, (until now ..;-))
The best way I found so far and it worked for 2 installation is (if you not have one yourself) get a backup copy through your hosting provider.(which contains [only] the WP files)
– Delete public_html/wp-content/themes/graphene
– than replace the “graphene” folder with the one from your back up
When you login into dashboard (for now) I would strongly recommend to not “update” Graphene theme again (if it shows up) until the issue is solved from Graphene themselves.