Upgrading Drupal

After upgrading from 8.2.7 to 8.3.0 my site throws this error:

Relevant system info:

Ubuntu 16.04.2
PHP 7.0.15
Apache 2.4.18
PostgreSQL 9.6.2

I've been trying to update to 8.3.0 using Drush which is installed globally and up to date

Site seems to work fine.
Status tells me that I must run update.php.
When I try, all I get is:

Drupal Database Update

I did set:

After updating my Drupal 7 site with new core files, the site is now blank.
I suspect it is the .htaccess file.
Can anybody help please?

Problem started after update to V7.54 . After update was getting message "Unknown toolbar item 'break'" when trying to access content through editor. Thought I would update from FCKeditor 2.6.6 to CKEditor 4.6.1, can't create new or edit exisiting wysiwyg profile

Any attempts to create or edit wysiwyg/profile returns: "The website encountered an unexpected error. Please try again later."

I've just upgraded my site from the lightning build 1.14 to 2.06 and in the process, I've lost "Save and keep published" from the content types to simply "Save". By allowing moderation on the content type, I get a "Moderation state" dropdown with different states in, but that appears half way up the page and I can't move it down as it doesn't appear in the the "manage form display" form.