Overview

The PHP variable “max_input_vars” was introduced in PHP 5.3.9+ as a security measure to limit the maximum amount of POST variables submitted, by default this limit is set to 1000.

In the Apache error log you will see an error like this:

"PHP Warning: Unknown: Input variables exceeded 1000. To increase the limit change max_input_vars in php.ini."

To resolve, the default value can be increased as per below.

Information

This was completely fixed in WordPress 4.5 and above. If you’re not running the latest version of WordPress, we highly recommend upgrading instead of making the changes below.

Shared Hosting

Create or update your .user.ini file and add the following line:

max_input_vars = 3000
max_input_vars error

VPS Hosting

  1. Log into Plesk.
  2. Click on PHP Settings:
    php settings
  3. At the bottom of the page in Additional configuration directives field add “max_input_vars” parameter with recommended value or greater: 
    max_input_vars = 3000
    max_input_vars error

Advice

The field “Additional configuration directives” in Plesk is only available to the Plesk Panel Administrator

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