Title: Fatal Error – duplicate wordpress
Last modified: September 10, 2018

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# Fatal Error – duplicate wordpress

 *  Resolved [Jejoi](https://wordpress.org/support/users/ejoi8/)
 * (@ejoi8)
 * [7 years, 9 months ago](https://wordpress.org/support/topic/fatal-error-duplicate-wordpress/)
 * Hi there,
 * I have my current wordpress site at “xxx.com” then, I want to duplicate the current
   wordpress site inside the current directory “xxx.com/dev” for development purpose.
 * The duplication process was working fine but I’ve got below error.
 * `Fatal error: Cannot declare class Swift_Performance, because the name is already
   in use in /public_html/dev/wp-content/plugins/swift-performance/performance.php
   on line 12`
 * Then I try to remove the **swift-performance** folder from the “xxx.com/dev/”
   plugin folder and everything works as it should be.
 * I noticed that swift plugins cause this kind of errors. How can I solve this?
 * note:
    public_html – current live wordpress directory public_html/dev – development
   wordpress directory
    -  This topic was modified 7 years, 9 months ago by [Jejoi](https://wordpress.org/support/users/ejoi8/).

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

 *  [Ivica Delic](https://wordpress.org/support/users/ivicad/)
 * (@ivicad)
 * [7 years, 8 months ago](https://wordpress.org/support/topic/fatal-error-duplicate-wordpress/#post-10757016)
 * Most likely you need to uninstall Swift from dev installation and have a clean/
   new Swift installation.
 *  Plugin Contributor [Fred](https://wordpress.org/support/users/fredawd/)
 * (@fredawd)
 * [7 years, 6 months ago](https://wordpress.org/support/topic/fatal-error-duplicate-wordpress/#post-10918812)
 * This thread has been marked as resolved due to lack of activity.
 * You’re always welcome to re-open this topic. Please read our faq before [open a new request](https://wordpress.org/support/topic/read-this-before-you-post-36/).
 * Thanks for understanding!
 *  [Rene Hermenau](https://wordpress.org/support/users/renehermi/)
 * (@renehermi)
 * [7 years, 5 months ago](https://wordpress.org/support/topic/fatal-error-duplicate-wordpress/#post-11047359)
 * This error is caused by the swift must-use plugin. It’s enough to delete the 
   swift must-use plugin from the folder wp-content/mu-plugins.
 * In the recent version of the Swift plugin, this error should be fixed already.

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

The topic ‘Fatal Error – duplicate wordpress’ is closed to new replies.

 * ![](https://ps.w.org/swift-performance-lite/assets/icon-256x256.jpg?rev=2388229)
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## Tags

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

 * 3 replies
 * 4 participants
 * Last reply from: [Rene Hermenau](https://wordpress.org/support/users/renehermi/)
 * Last activity: [7 years, 5 months ago](https://wordpress.org/support/topic/fatal-error-duplicate-wordpress/#post-11047359)
 * Status: resolved