Thank you @modernnerd thats it!
Everything works fine now!
Thanks @studiopress for the fast response!
In my case everything works great when I deactivate AB manually. But Genesis Blocks still thinks it need a migration in the Backend.
same here. It fails on the very last step of migration.
I did some research:
After enabling WordPress Debugging this is written to the Logfile:
PHP Fatal error: Cannot redeclare get_plugin_data() (previously declared in /path/to/wp/wp-admin/includes/plugin.php:68) in /path/to/wp/wp-admin/includes/plugin.php on line 68
Maybe that helps?