I’m in the process of moving “all” of my sites from Canvas to GP, and have successfully done so with several sites without problem. On the latest, however, WP puts up the following errors at the top of the page when trying to activate GP:
Warning: array_merge(): Argument #4 is not an array in /home/account/public_html/wp-includes/widgets.php on line 1159
Warning: array_diff(): Argument #2 is not an array in /home/account/public_html/wp-includes/widgets.php on line 1160
Warning: Invalid argument supplied for foreach() in /home/account/public_html/wp-includes/widgets.php on line 1162
Warning: array_merge(): Argument #1 is not an array in /home/account/public_html/wp-includes/widgets.php on line 1170
The site is WordPress 4.9.4, latest GP, and this is before I even attempt to activate GP Premium. On this site, if needed I can create an account for you to poke around and see what’s up.