Title: Plugin cannot be deactivated
Last modified: August 22, 2016

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# Plugin cannot be deactivated

 *  Resolved [chivkea](https://wordpress.org/support/users/chivkea/)
 * (@chivkea)
 * [11 years, 3 months ago](https://wordpress.org/support/topic/plugin-cannot-be-deactivated/)
 * Hello, I can’t seem to deactivate your plugin. It returns a blank page. Any suggestion?
 * [https://wordpress.org/plugins/nextgen-gallery-optimizer/](https://wordpress.org/plugins/nextgen-gallery-optimizer/)

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

 *  Plugin Author [Mark Jeldi](https://wordpress.org/support/users/mark-jeldi/)
 * (@mark-jeldi)
 * [11 years, 2 months ago](https://wordpress.org/support/topic/plugin-cannot-be-deactivated/#post-5849815)
 * Hi [@chivkea](https://wordpress.org/support/users/chivkea/),
 * Thanks for using NextGEN Gallery Optimizer, and apologies for any inconvenience.
 * The blank page you’re experiencing is due to a fatal error caused by the **major
   NextGEN Gallery v2.0.7x update**, 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.
 * The reason the plugin won’t deactivate properly, is due to the presence of a 
   fatal error (only visible when WP_DEBUG is active), which is caused by the complete
   removal of the C_Lightbox_Installer class (and its uninstall_lightbox() method)
   in NextGEN Gallery v2.0.7x.
 * 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**.
 * 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.
 *  [BMHIexeter](https://wordpress.org/support/users/bmhiexeter/)
 * (@bmhiexeter)
 * [11 years, 2 months ago](https://wordpress.org/support/topic/plugin-cannot-be-deactivated/#post-5849865)
 * I tried to add a plugin I just purchased and it can’t except dut to a fatal error
   from your “nextgen-gallery-optimizer”. I tried to deactivate or delete and It
   reads:
 * Fatal error: Call to undefined method C_Lightbox_Installer::uninstall_lightbox()
   in /home/content/p3pnexwpnas03_data02/06/2443206/html/wp-content/plugins/nextgen-
   gallery-optimizer/admin/assets/install/class-nggobasic-lightbox-installer-nextgen-
   v2.php on line 201
 * I need you to reimburse me the $$$ I just purchased on this new plugin tool or
   explain how I can deactivate ASAP. Thanks:)
 *  Plugin Author [Mark Jeldi](https://wordpress.org/support/users/mark-jeldi/)
 * (@mark-jeldi)
 * [11 years, 2 months ago](https://wordpress.org/support/topic/plugin-cannot-be-deactivated/#post-5849892)
 * Hi [@bmhiexeter](https://wordpress.org/support/users/bmhiexeter/),
 * Just so other readers are clear, the unnamed plugin you have purchased a license
   for is NOT Optimizer Pro.
 * And, for some context, you are using a free version of [a GPL-licensed product](http://www.gnu.org/licenses/gpl-2.0.txt)(
   i.e. PROVIDED “AS IS” WITHOUT WARRANTY OF ANY KIND), yet are requesting (if not
   demanding) either free support, or financial compensation for incompatibility
   with some other author’s _premium_ product. Not cool.
 * With that said, I would be happy to help you out, but have you read the immediately
   preceding post in this support topic (or the [full-screen notice at the top of Optimizer’s main plugin page](https://wordpress.org/plugins/nextgen-gallery-optimizer/)),
   at all? It fully details everything you need to know regarding this issue, including
   the actual cause, and how to fix it.
 * I’ll post it again for you (so you get it via email), and I’ll include some extra
   links you might find helpful in rolling-back.
 * Do let me know if you have any questions or further issues, and many apologies
   in advance for any inconvenience caused.
 * …
 * The blank page you’re experiencing is due to a fatal error caused by the **major
   NextGEN Gallery v2.0.7x update**, 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.
 * The reason the plugin won’t deactivate properly, is due to the presence of a 
   fatal error, which is caused by the complete removal of the C_Lightbox_Installer
   class (and its uninstall_lightbox() method) in NextGEN Gallery v2.0.7x (hence
   the error message _text_ you’re seeing).
 * 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/plugin-cannot-be-deactivated/#post-5849942)
 * Hi [@chivkea](https://wordpress.org/support/users/chivkea/) and [@bmhiexeter](https://wordpress.org/support/users/bmhiexeter/),
 * 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 blank screen/fatal error issues caused by NextGEN v2.0.71
   + that you’ve both 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 4 replies - 1 through 4 (of 4 total)

The topic ‘Plugin cannot be deactivated’ 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/)

 * 4 replies
 * 3 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/plugin-cannot-be-deactivated/#post-5849942)
 * Status: resolved