Title: Plugin does not have valid header
Last modified: August 20, 2016

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# Plugin does not have valid header

 *  [NathanCorbier](https://wordpress.org/support/users/nathancorbier/)
 * (@nathancorbier)
 * [13 years, 3 months ago](https://wordpress.org/support/topic/plugin-does-not-have-valid-header-2/)
 * As WP states, the plugin does not have a valid header when attempting to activate.
 * [http://wordpress.org/extend/plugins/all-in-one-event-calendar/](http://wordpress.org/extend/plugins/all-in-one-event-calendar/)

Viewing 4 replies - 1 through 4 (of 4 total)

 *  [Xavi79](https://wordpress.org/support/users/xavi79/)
 * (@xavi79)
 * [13 years, 3 months ago](https://wordpress.org/support/topic/plugin-does-not-have-valid-header-2/#post-3464599)
 * Hi,
 * same problem on WP 3.3.1.
 * then I try to mv /wordpress/wp-content/plugins/all-in-one/all-in-one.php to plugins
   root (..nt/plugins/all-in-one.php) but after that, when try to active plugin,
   fatal error:
 * `Warning: require_once(/usr/share/wordpress/wp-content/plugins/lib/iCalcreator-
   2.14/iCalcreator.class.php): failed to open stream: No such file or directory
   in /usr/share/wordpress/wp-content/plugins/all-in-one-event-calendar.php on line
   249 Fatal error: require_once(): Failed opening required '/usr/share/wordpress/
   wp-content/plugins/lib/iCalcreator-2.14/iCalcreator.class.php' (include_path='.:/
   usr/share/php:/usr/share/pear') in /usr/share/wordpress/wp-content/plugins/all-
   in-one-event-calendar.php on line 249`
 * Any help will be greatly appreciated 😉
 *  [David van Diepen](https://wordpress.org/support/users/david-van-diepen/)
 * (@david-van-diepen)
 * [13 years, 3 months ago](https://wordpress.org/support/topic/plugin-does-not-have-valid-header-2/#post-3464611)
 * hey, i had the same problem, but after going to the full plugin list, I was able
   to activate it after all. This article was really helpfull for me:
 * [http://webdesign.anmari.com/2312/activation-error-plugin-does-not-have-valid-header-still-activates/](http://webdesign.anmari.com/2312/activation-error-plugin-does-not-have-valid-header-still-activates/)
 * good luck!
 *  [Ian Parkinson](https://wordpress.org/support/users/ianpark/)
 * (@ianpark)
 * [12 years, 11 months ago](https://wordpress.org/support/topic/plugin-does-not-have-valid-header-2/#post-3464618)
 * All I did was open the file all-in-one-event-calendar.php in the root of the 
   plugin and on the first lines change the initial /** to /*
 * Then I went back and reactivated it. That got it working, and it took me to a
   splash page that said “All-in-One Event Calendar Notice: You are using the Lite
   Calendar. This edition of the plugin is no longer supported” And then a button
   to “Upgrade to the Standard Calendar for free”
    I pressed that which installed
   an update, then automatically removed the old plugin. Now it works fine 🙂
 *  [SweetPweb](https://wordpress.org/support/users/sweetpweb/)
 * (@sweetpweb)
 * [12 years, 11 months ago](https://wordpress.org/support/topic/plugin-does-not-have-valid-header-2/#post-3464619)
 * I had the same issue and the solution above worked for me as well. Thanks Ian.

Viewing 4 replies - 1 through 4 (of 4 total)

The topic ‘Plugin does not have valid header’ is closed to new replies.

 * ![](https://s.w.org/plugins/geopattern-icon/all-in-one-event-calendar.svg)
 * [Timely All-in-One Events Calendar](https://wordpress.org/plugins/all-in-one-event-calendar/)
 * [Support Threads](https://wordpress.org/support/plugin/all-in-one-event-calendar/)
 * [Active Topics](https://wordpress.org/support/plugin/all-in-one-event-calendar/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/all-in-one-event-calendar/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/all-in-one-event-calendar/reviews/)

## Tags

 * [valid header](https://wordpress.org/support/topic-tag/valid-header/)

 * 4 replies
 * 5 participants
 * Last reply from: [SweetPweb](https://wordpress.org/support/users/sweetpweb/)
 * Last activity: [12 years, 11 months ago](https://wordpress.org/support/topic/plugin-does-not-have-valid-header-2/#post-3464619)
 * Status: not resolved