Title: Fatal error on customize
Last modified: August 30, 2016

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# Fatal error on customize

 *  [BillGhai](https://wordpress.org/support/users/billghai/)
 * (@billghai)
 * [10 years, 7 months ago](https://wordpress.org/support/topic/fatal-error-on-customize/)
 * Hello
 * I am trying to install the Rational Start Theme and I get this error
 * Fatal error: Call to undefined function boolval() in /homepages/6/d539165582/
   htdocs/flightofthebirds/blog/wp-content/themes/rational-start/inc/theme_setup.
   php on line 75

The topic ‘Fatal error on customize’ is closed to new replies.

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   jpg)
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 * 0 replies
 * 1 participant
 * Last reply from: [BillGhai](https://wordpress.org/support/users/billghai/)
 * Last activity: [10 years, 7 months ago](https://wordpress.org/support/topic/fatal-error-on-customize/)
 * Status: not resolved