I have strange situation which just started which I seem to be unable to resolved. I am not sure what this might be related to but I think I remember reading somewhere that this has happened to someone else.

Upon logging into WordPress then going into the menu management area, then clicking on "screen options" and enabling the view of a menu metabox for a custom post type that was created and then adding a page from that post type to the menu the menu management area started showing a Internal Server Error 500 message.

Every other area of the website and admin area works perfectly except for the menu management link. I have attempted everything I can think of in an effort to resolve the problem including removing every plugin and customization made to my functions.php file however I can't get the issue resolved.

I was hoping someone here might able to help me resolve this issue or suggest anything to diagnose this issue.

Any help is greatly appreciated!

  • Any odds you've zillions of pages or terms? If so, look no further. WP menus just don't scale when loads of content is present. Commented Oct 13, 2010 at 18:17

3 Answers 3


I just figured out my own issue which I am hoping might help others if they get stuck in this situation.

Essentially the problem seemed to be that modsecurity caused the 500 Internal Server error because for some reason (which I have yet to understand) the menu page was sending a bunch of data in the response body.

To resolve the problem I just needed to add the following to my vhost.conf file and restart apache. Here I doubled the response body size.

SecResponseBodyLimit 1572864
  • 1 572 864 = 1 536k or 1.5 Megabyte. Now that's what I call an Ajax request size. Probably you should not use Wordpress build-in menus.
    – hakre
    Commented Oct 14, 2010 at 20:59
  • @hakre -- Yeah, it was really confusing to me as to why the backend menu management screen was creating a 500 error. What I was unable to figure out was the size of the ajax request the menu management page was creating. Do you happen to know how to figure that out? (firebug?) Also, I have like 8 custom post types and 4 custom taxonomies which in turn create a bunch of metaboxes but I was assuming its the wordpress code which might be sending too much data. Any ideas? Commented Oct 14, 2010 at 22:11
  • modsecurity seems to be very suspicious towards some of AJAX stuff in WordPress. I had to ask my hosting (shared) to whitelist several related files or simply having post editor open would generate 500 error every minute in background, etc.
    – Rarst
    Commented Oct 16, 2010 at 9:25
  • Looks like this is under discussion here: core.trac.wordpress.org/ticket/14134 Commented Oct 16, 2010 at 12:46
  • thats good to know... btw does anyone know of a safe settings for the SecResponseBodyLimit till this is resolved? Commented Oct 18, 2010 at 10:22

I experienced the same problem. For some reason WordPress inserts the complete text of the post into the description of each menu element, making it very heavy to upload when there are several elements. Just modify (shorten) or delete this description and changes will be saved with no 500 error. It worked for me.

  • Thanks, this works!
    – physixfan
    Commented Jan 10, 2021 at 18:56

I got around this by updating the menu via Appearances > Customise > Menus

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