Direct after upgrading to 3.4 I noticed Illegal string offset 'total_users' in update.php on line 75.
On line 55 it requests
$user_count = get_user_count( );
I echo this value and it is an integer (2) so not an array
on line 73 however it requests
(so an array..... ) this is where it fails on my WP multisite install.
So im thinking what could be wrong since my get_user_count() does not return an array but just "2" (so an integer)
(but obviously this should be an array since it has been an array for always)