Troubleshooting WordPress – Unable to add more menus
Websites often use lots of Menus, but some websites can use an enormous amount; especially when using large forms (such as survey or detailed contact forms).
In cases such as these, the default upper limit for adding new menu's can be hit and WordPress will seemingly stop allowing you to add new menu's without any explanation.
Enabling Error Reporting
First things first, it's important to confirm what is causing the issue and as WordPress (by default) doesn't have error reporting enabled, we are going to have to enable it.
Open up your wp-config file in our inbuilt text editor (which you can find in public_html) by right clicking the file and either clicking “Edit Text File” if you're on the cloud, or “Edit” if you're on cPanel.
A few lines from the bottom of the file you will see
And to enable the debug mode, simply change “false” to “true”.
Now when your WordPress installation hits an error, rather than leaving everybody guessing, it will display the error on your page which you can let our Support team know about.
Once you have a copy of the error message it's recommeneded that you set the debugging mode back to “false”.
The Most Likely cause
As mentioned at the beginning, if you've encountered this issue after having already added a sizable number of menus, chances are you have hit the default upper limit for menu items.
warning: parse_str() [function.parse-str]: Input variables exceeded 1000. To increase the limit change max_input_vars in php.ini. in/home/user/public_html/path/t0/file/causing/this/error.php on line 459
If the error you saw after enabling debug mode looked something like this (specifically looking for “input variables exceeded”), the most likely cause is that you need your “Max_Input_Vars” limit increased. By default this is set to 1000 (which amounts to roughly 80 menu items).
To get this limit increased, simply let our support team know and we can get that done for you.
A Helpful Plugin
Just because there is an easy fix to the issue doesn't mean we should wait until it's effecting your WordPress site to do anything! So, as a preventative and informative measure, we recommend downloading the “Menu Item Limit Detector”
This plugin, which you can download here (http://sevenspark.com/wordpress/menu-item-limit) will let you know when you're approaching the Max_Input_Vars limit by displaying an error message in your “Menu” page that looks something like this
If you have this plugin enabled, and you see this error message, let the support team know that you're approaching your default Max_Input_Vars limit and we can increase it for you before it becomes a problem