After update menu items broken; page parent/child settings off

Have to tried to reset the parent page in the editor where you are showing the no parent in the screen shot? When you say you reset the permalinks did you set them to default and try it? What does the htaccess file look like?

There’s a thread and a fix here that might get you further.

https://www.ads-software.com/support/topic/secondary-or-child-pages-returning-a-404-error-after-wp-34-update?replies=11

Hi Radices – thank you

I have tried to reset the parent page in the editor – but the parent page is not in the list.

Kindly note the actual number of pages is 73, but only 10 of the site’s pages appear as possible parents.

I will try to see what happens when using default permalink setting.

Setting permalinks to “plain” does result in menu links that go to the intended pages.

But restoring the desired setting to postname also restores the broken link problem.

I will try the solution you linked to, namely adding this to the child theme functions.php:

global $wp_rewrite; $wp_rewrite->flush_rules();

Adding this code to functions.php and refreshing website did not fix the problem:

global $wp_rewrite; $wp_rewrite->flush_rules();

So I think I will try to restore a backup of the database.

Hi!
Same problem here. Did anyone find a different solution than restoring from backup?
I, of course, did not make a backup before updating.

Hi again.
I am pretty desperate ??
Does anybody know a workaround solution? Maybe editing the database? I tried searching the database for these links but could not find them.
Even a very time consuming solution would work for me.

After I tried everything and after my page broke down completely I managed to correct the problem.
The problem was with the theme I was using. I downgraded to WordPress 4.3 but this did not solve the issue. Then I deactivated all the plugins – no success. Then I did the same with the theme and after I reactivated it, everything was back to normal.