Title: Installed, but fatal error on activation
Last modified: August 30, 2017

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# Installed, but fatal error on activation

 *  [freshpromo](https://wordpress.org/support/users/freshpromo/)
 * (@freshpromo)
 * [8 years, 7 months ago](https://wordpress.org/support/topic/installed-but-fatal-error-on-activation/)
 * I’m using WP 4.8.1, running PHP 5.2 on the server. I’ve installed the plugin 
   on a WordPress Network site but it won’t activate. I get the following error.
   Please help!
 * Plugin could not be activated because it triggered a fatal error.
 * Warning: require_once(__DIR__/vendor/autoload.php) [function.require-once]: failed
   to open stream: No such file or directory in /home/***/public_html/***.ca/wordpress/
   wp-content/plugins/php-compatibility-checker/wpengine-phpcompat.php on line 15
 * Fatal error: require_once() [function.require]: Failed opening required ‘__DIR__/
   vendor/autoload.php’ (include_path=’.:/opt/alt/php52/usr/share/pear:/opt/alt/
   php52/usr/share/php’) in /home/***/public_html/***.ca/wordpress/wp-content/plugins/
   php-compatibility-checker/wpengine-phpcompat.php on line 15

Viewing 5 replies - 1 through 5 (of 5 total)

 *  [cecilia99](https://wordpress.org/support/users/cecilia99/)
 * (@cecilia99)
 * [8 years, 7 months ago](https://wordpress.org/support/topic/installed-but-fatal-error-on-activation/#post-9511622)
 * I am having the same problem and even worse it won’t let me delete the plugin.
   Please advise. Thank you!
 *  Thread Starter [freshpromo](https://wordpress.org/support/users/freshpromo/)
 * (@freshpromo)
 * [8 years, 7 months ago](https://wordpress.org/support/topic/installed-but-fatal-error-on-activation/#post-9511633)
 * [@cecilia99](https://wordpress.org/support/users/cecilia99/)
    You should be able
   to remove it if you login via FTP, go to wp-content/plugins/ and delete the ‘
   php-compatibility-checker’ folder.
 * Also, what version of PHP is installed on the server? You can find out by logging
   into cPanel and going to Software > Select PHP versions. If it’s 5.2 like me,
   I suspect that is causing the problem. Only a guess on my part, though many wordpress
   plugins are developed to only work on PHP 5.3 and above.
 *  [cecilia99](https://wordpress.org/support/users/cecilia99/)
 * (@cecilia99)
 * [8 years, 7 months ago](https://wordpress.org/support/topic/installed-but-fatal-error-on-activation/#post-9519916)
 * You were right it was 5.2 it worked when I upgraded to 5.6. Thanks!
 *  [Marty](https://wordpress.org/support/users/bozzmedia/)
 * (@bozzmedia)
 * [8 years, 4 months ago](https://wordpress.org/support/topic/installed-but-fatal-error-on-activation/#post-9751314)
 * Just encountered this error on a PHP 5.2 site and can confirm this plugin does
   not currently work with PHP 5.2.
 *  [Marty](https://wordpress.org/support/users/bozzmedia/)
 * (@bozzmedia)
 * [8 years, 4 months ago](https://wordpress.org/support/topic/installed-but-fatal-error-on-activation/#post-9754573)
 * I incremented PHP up to 5.4 and was able to activate the plugin fine. Definitely
   seems to be an issue with running this plugin with PHP 5.2.

Viewing 5 replies - 1 through 5 (of 5 total)

The topic ‘Installed, but fatal error on activation’ is closed to new replies.

 * ![](https://ps.w.org/php-compatibility-checker/assets/icon-256x256.png?rev=1446087)
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## Tags

 * [fatal error](https://wordpress.org/support/topic-tag/fatal-error/)

 * 5 replies
 * 3 participants
 * Last reply from: [Marty](https://wordpress.org/support/users/bozzmedia/)
 * Last activity: [8 years, 4 months ago](https://wordpress.org/support/topic/installed-but-fatal-error-on-activation/#post-9754573)
 * Status: not resolved