Code Igniter Error: Disallowed Key Characters

1. Search for function _clean_input_keys on /system/core/Input.php

2. Modify this line

exit(‘Disallowed Key Characters.’);


exit(‘Disallowed Key Characters.’ .  $str);

3. Refresh page to see the characters which generate the error

4. If you need to add those characters into the exception list, just add to this line

if ( ! preg_match(“/^[a-z0-9:_\/-]+$|/i”, $str))

I add | (pipe) character on the example above

Note: In most cases you can resolve the problem just by clearing the cookies