Title: Cannot activate plugins
Last modified: August 22, 2016

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# Cannot activate plugins

 *  Resolved [arron_v](https://wordpress.org/support/users/arron_v/)
 * (@arron_v)
 * [11 years, 2 months ago](https://wordpress.org/support/topic/cannot-activate-plugins-2/)
 * HI,
 * I can no longer activate plugins on my site since installing this plugin.
 * I get the following error:
    Fatal error: Class ‘C_NextGen_Settings’ not found
   in /home/content/f/l/i/flityr/html/hls/wordpress/wp-content/plugins/nextgen-gallery-
   optimizer/admin/assets/install/class-nggobasic-fancybox-installer-nextgen-v2.
   php on line 197
 * I have tried deactivating and deleting this plugin and Nextgen gallery but the
   error persists.
 * Tired re-installing etc. I need Nextgen to work but also need to activate some
   new plugins.
 * How do I fix it?
 * Thanks
 * [https://wordpress.org/plugins/nextgen-gallery-optimizer/](https://wordpress.org/plugins/nextgen-gallery-optimizer/)

Viewing 2 replies - 1 through 2 (of 2 total)

 *  Plugin Author [Mark Jeldi](https://wordpress.org/support/users/mark-jeldi/)
 * (@mark-jeldi)
 * [11 years, 2 months ago](https://wordpress.org/support/topic/cannot-activate-plugins-2/#post-5856870)
 * Hi [@arron_v](https://wordpress.org/support/users/arron_v/),
 * Thanks for using NextGEN Gallery Optimizer, and apologies for any inconvenience.
 * The fatal error you’re experiencing is caused by the **major NextGEN Gallery 
   v2.0.7x update**, initially released recently on the 19th of February 2015. Unfortunately,
   [as I’ve detailed on Optimizer’s main plugin page](https://wordpress.org/plugins/nextgen-gallery-optimizer/),
   Optimizer is not currently fully compatible with this release.
 * As key parts of the NextGEN v2.0 API were completely removed in this update (
   without any graceful deprecation, or backwards-compatibility in place), Optimizer(
   and likely many other NextGEN extensions) will display fatal errors, and not 
   function correctly with this release, until all affected integration components
   are rewritten.
 * I’ve been hard at work on the next update for Optimizer (including full support
   for NextGEN v2.0.7x), and I should have it ready for release in the next few 
   days, after thorough testing. In the meantime, however, and to ensure a smooth
   update process, I would recommend rolling-back to the immediately-preceding, 
   fully-compatible, stable release of NextGEN v2.0.66.37.
 * You can find the download at the following link…
    [http://wordpress.org/plugins/nextgen-gallery/developers/](http://wordpress.org/plugins/nextgen-gallery/developers/)
 * And here’s a good step-by-step guide…
    [http://www.nextgen-gallery.com/how-to-rollback-a-version/](http://www.nextgen-gallery.com/how-to-rollback-a-version/)
 * Optimizer’s broad, existing compatibility with NextGEN (v2.0.0 to v2.0.66.37),
   NextGEN Legacy (v1.6.2 to v1.9.13) and NextCellent Gallery remains unaffected.
 * I hope this helps, and thank you for your patience.
 * Cheers,
    Mark.
 *  Plugin Author [Mark Jeldi](https://wordpress.org/support/users/mark-jeldi/)
 * (@mark-jeldi)
 * [11 years, 2 months ago](https://wordpress.org/support/topic/cannot-activate-plugins-2/#post-5857100)
 * Hi again [@arron_v](https://wordpress.org/support/users/arron_v/),
 * As promised, I’m pleased to say I’ve just finished releasing the major compatibility
   update of [Optimizer v2.1](https://wordpress.org/plugins/nextgen-gallery-optimizer/),
   which now features (amongst many other things) full compatibility with the major
   update of NextGEN Gallery v2.0.71 (up to the current v2.0.77).
 * This version fixes the plugins not activating/fatal error issues caused by NextGEN
   v2.0.71+ that you’ve experienced, and I encourage you to update at your earliest
   convenience.
 * As always, you can update to Optimizer v2.1 via the plugins page in your WordPress
   admin, or by downloading it from [Optimizer’s main plugin page](https://wordpress.org/plugins/nextgen-gallery-optimizer/)
   here at WordPress.org.
 * For the full list of improvements and additions in Optimizer v2.1, please see…
   
   [http://www.nextgengalleryoptimizer.com/blog/nextgen-gallery-optimizer-v2-1-now-available/](http://www.nextgengalleryoptimizer.com/blog/nextgen-gallery-optimizer-v2-1-now-available/)
 * Thanks again for your patience during this period. I’ll now mark this topic as
   resolved.
 * All the best,
    Mark.

Viewing 2 replies - 1 through 2 (of 2 total)

The topic ‘Cannot activate plugins’ is closed to new replies.

 * ![](https://ps.w.org/nextgen-gallery-optimizer/assets/icon.svg?rev=1183755)
 * [NextGEN Gallery Optimizer](https://wordpress.org/plugins/nextgen-gallery-optimizer/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/nextgen-gallery-optimizer/#faq)
 * [Support Threads](https://wordpress.org/support/plugin/nextgen-gallery-optimizer/)
 * [Active Topics](https://wordpress.org/support/plugin/nextgen-gallery-optimizer/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/nextgen-gallery-optimizer/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/nextgen-gallery-optimizer/reviews/)

 * 2 replies
 * 2 participants
 * Last reply from: [Mark Jeldi](https://wordpress.org/support/users/mark-jeldi/)
 * Last activity: [11 years, 2 months ago](https://wordpress.org/support/topic/cannot-activate-plugins-2/#post-5857100)
 * Status: resolved