Appearance/menus error

“a critical error”

Errors like this are logged. Check the error log on your server. If you can’t find the log, please contact your host.

Meantime, enable wp_debug and wp_debug_log and after an error, look at wp-content/debug.log to see if anything gets logged there. https://www.ads-software.com/support/article/debugging-in-wordpress/

You can also try this: Please attempt to disable all plugins, and use one of the default (Twenty*) themes. If the problem goes away, enable them one by one to identify the source of your troubles.

If you cannot access wp-admin, there are other ways to deactivate plugins:  https://www.ads-software.com/support/article/faq-troubleshooting/#how-to-deactivate-all-plugins-when-not-able-to-access-the-administrative-menus

This is what I find in Debug log manager when site is in Troubleshooting mode and I click Menus via Appearance:

PHP Fatal Uncaught Error: Attempt to assign property “posts_page” on null
Stack trace: 0 /wp-admin/includes/template.php(1577): wp_nav_menu_item_post_type_meta_box(NULL, Array) 1 /wp-admin/nav-menus.php(984): do_accordion_sections(Object(WP_Screen), ‘side’, NULL) 2 {main} thrown in /wp-admin/includes/nav-menu.php on line 406

WordPress core
File: /wp-admin/includes/nav-menu.php
Line: 406

Advice will be appreciated

I was hoping for more debug entries than that. Well, then, on to more troubleshooting. This may be a plugin or theme conflict. Please attempt to disable all plugins, and use one of the default (Twenty*) themes. If the problem goes away, enable them one by one to identify the source of your troubles.

Thanks for your feedback. I did your troubleshooting and when all plugins are disabled and Twenty theme active I get the debug entry as shown in my earlier message. I have more than 100 log entries since this morning- -php deprecated, php warnings, etc. Examples- 36 of each of:

PHP Warning Undefined array key “file”
WordPress core
File: /wp-includes/media.php
Line: 1373

PHP Deprecatedstrpos(): Passing null to parameter #1 ($haystack) of type string is deprecatedWordPress core
File:?/wp-includes/media.php
Line: 1373

Plugin related example- 116 occurrences

PHP Deprecated Automatic conversion of false to array is deprecated
Plugin: WP Super Cache
File: /wp-content/plugins/wp-super-cache/wp-cache-phase2.php
Line: 984

The problem is that that’s where the error is being detected, not where it’s caused.

Long shot: Go to DASHBOARD -> UPDATES and click the button to reinstall WP. That will replace the files and make sure you have a consistent set. (You will not lose any data.)

I did the WP reinstall, but the Appearance/Menus error “Attempt to assign property “posts_page” on null” does not go away. Debug log shows lots of “PHP deprecated” items also “PHP warnings”. “Fatal PHP” messages on log are:

[24-Jul-2023 07:10:43 UTC] PHP Fatal error Cannot declare class Debug_Bar, because the name is already in use

[24-Jul-2023 08:28:18 UTC]?PHP Fatal error?Uncaught Error: Attempt to assign property “posts_page” on null?

[25-Jul-2023 16:27:26 UTC]?PHP Fatal error?Allowed memory size of 536870912 bytes exhausted (tried to allocate 1052672 bytes)?(This is linked to a backup)

Further suggestions will be appreciated

This is a known issue, that will be fixed in WordPress 6.3. This is the ticket:

https://core.trac.www.ads-software.com/ticket/58345

To fix this right now, you would need to make a change in the database in the wp_options table. Look for the option_key with the name page_for_posts and change the value to 0 after which you should be able to change your settings again via your dashboard.

Hi Jos, Thank you for the assistance. Problem solved. I could not find the name “page_for_posts” but found “posts_per_page” with a value of 10 which we changed to 0.

Glad to hear it’s solved, but that other setting should not be changed. It’s the number of posts that’s shown on a blog page.

If page_for_posts is not available, it might also be the option page_on_front.