Title: Fatal error: Call to undefined function mcrypt_decrypt()
Last modified: August 20, 2016

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# Fatal error: Call to undefined function mcrypt_decrypt()

 *  Resolved [LeeTheGreenGiant](https://wordpress.org/support/users/leethegreengiant/)
 * (@leethegreengiant)
 * [13 years, 1 month ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-mcrypt_decrypt/)
 * Hi Dave,
 * Just found your plugin today, played around with it and love it. So I purchased
   an upgrade and when I entered the key it produced a Fatal Error. Here’s the full
   message I get.
 * > Fatal error: Call to undefined function mcrypt_decrypt() in /var/www/vhosts/
   > wroxhamtla.org.uk/httpdocs/wp-content/plugins/kontrol-developer-kit/app/classes/
   > Admin.class.php on line 271
 * I would be really grateful if you could help me out here. Hopefully it’s something
   simple.
 * Also, I’ve just checked the Admin.class.php file and it’s the path_check() function
   that’s producing the error.
 * Many thanks,
    Lee
 * [http://wordpress.org/extend/plugins/kontrol-developer-kit/](http://wordpress.org/extend/plugins/kontrol-developer-kit/)

Viewing 3 replies - 1 through 3 (of 3 total)

 *  Plugin Author [Kontrolwp](https://wordpress.org/support/users/kontrolwp/)
 * (@kontrolwp)
 * [13 years, 1 month ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-mcrypt_decrypt/#post-3620245)
 * Hey Lee,
 * Ah sorry about your troubles mate. Looks like your server doesn’t have the mcrypt_decrypt
   module for PHP. I’ve had one other person report this problem and they were running
   Plesk and just guessing by looking at your path above, you’re running it as well.
   The module is pretty common, but unfortunately missing from some Plesk installations.
 * To get you up and running in the mean time, send me an email at david(at)kontrolwp.
   com and I’ll send you back a file which can activate Kontrol using another method
   other than mcrypt_decrypt. This should get you by until the next release of Kontrol(
   still a bit away) which will then overwrite the file I give you and go back to
   using mcrypt. You might also want to ask your server admin to install the module
   for you in the mean time, that might also be a quick workaround.
 * If this problem persists, I’ll look at writing a permanent solution for Plesk
   users that don’t have the module installed.
 * Thanks for the kind words too, hope that helps,
    Dave.
 *  Thread Starter [LeeTheGreenGiant](https://wordpress.org/support/users/leethegreengiant/)
 * (@leethegreengiant)
 * [13 years, 1 month ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-mcrypt_decrypt/#post-3620340)
 * Hi Dave,
 * Thanks for the quick response. I’ve been in contact with my web host company 
   and they have installed the mcrypt_decrypt onto my VPS and now it’s all working
   fine. Yey!
 * Thank you again for answering this so quickly and coming to a solution.
 * I will definitely recommend your plugin.
 * All the best,
    Lee
 *  Plugin Author [Kontrolwp](https://wordpress.org/support/users/kontrolwp/)
 * (@kontrolwp)
 * [13 years, 1 month ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-mcrypt_decrypt/#post-3620400)
 * That’s great to hear Lee, enjoy the plugin mate!

Viewing 3 replies - 1 through 3 (of 3 total)

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## Tags

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

 * 3 replies
 * 2 participants
 * Last reply from: [Kontrolwp](https://wordpress.org/support/users/kontrolwp/)
 * Last activity: [13 years, 1 month ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-mcrypt_decrypt/#post-3620400)
 * Status: resolved