Title: Fatal Error when using Migration File Extension
Last modified: May 30, 2023

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# Fatal Error when using Migration File Extension

 *  Resolved [snippet24](https://wordpress.org/support/users/snippet24/)
 * (@snippet24)
 * [3 years ago](https://wordpress.org/support/topic/fatal-error-when-using-migration-file-extension/)
 * Detail of the error (do note this happens in localhost with latest version of
   the main plugin in the import page):
 * Fatal error: Uncaught Error: Undefined constant “AI1WM_MAX_FILE_SIZE” in E:\website\
   www\wordpress\wp-content\plugins\all-in-one-wp-migration-file-extension\lib\controller\
   class-ai1wmte-main-controller.php:131 Stack trace: #0 E:\website\www\wordpress\
   wp-includes\class-wp-hook.php(308): Ai1wmte_Main_Controller->enqueue_import_scripts_and_styles()#
   1 E:\website\www\wordpress\wp-includes\class-wp-hook.php(332): WP_Hook->apply_filters()#
   2 E:\website\www\wordpress\wp-includes\plugin.php(517): WP_Hook->do_action() #
   3 E:\website\www\wordpress\wp-admin\admin-header.php(118): do_action() #4 E:\
   website\www\wordpress\wp-admin\admin.php(239): require_once(‘…’) #5 {main} thrown
   in E:\website\www\wordpress\wp-content\plugins\all-in-one-wp-migration-file-extension\
   lib\controller\class-ai1wmte-main-controller.php on line 131
    -  This topic was modified 3 years ago by [snippet24](https://wordpress.org/support/users/snippet24/).

Viewing 5 replies - 1 through 5 (of 5 total)

 *  Thread Starter [snippet24](https://wordpress.org/support/users/snippet24/)
 * (@snippet24)
 * [2 years, 12 months ago](https://wordpress.org/support/topic/fatal-error-when-using-migration-file-extension/#post-16822782)
 * Maybe there’s no longer support of it?
 *  [Monoloid](https://wordpress.org/support/users/monoloid/)
 * (@monoloid)
 * [2 years, 11 months ago](https://wordpress.org/support/topic/fatal-error-when-using-migration-file-extension/#post-16843674)
 * Need to downgrade to PHP 7.
 *  Thread Starter [snippet24](https://wordpress.org/support/users/snippet24/)
 * (@snippet24)
 * [2 years, 11 months ago](https://wordpress.org/support/topic/fatal-error-when-using-migration-file-extension/#post-16853263)
 * Thanks for the hint! I still think though this PHP 8 issue should be addressed
   by the plugin devs.
 *  Plugin Author [Yani](https://wordpress.org/support/users/yaniiliev/)
 * (@yaniiliev)
 * [2 years, 10 months ago](https://wordpress.org/support/topic/fatal-error-when-using-migration-file-extension/#post-16921384)
 * Could you please deactivate the File Extension and try again?
 * It’s important to note that the “all-in-one-wp-migration-file-extension” plugin
   has been deprecated for more than two years. This means that it’s no longer recommended
   to use it as it may cause compatibility issues with other plugins, including 
   the latest version of the All-in-One WP Migration plugin.
 * Therefore, I would recommend that you deactivate the “all-in-one-wp-migration-
   file-extension” plugin and rely solely on the latest version of the All-in-One
   WP Migration plugin. This should help resolve any warnings that you’re experiencing.
 *  Thread Starter [snippet24](https://wordpress.org/support/users/snippet24/)
 * (@snippet24)
 * [2 years, 10 months ago](https://wordpress.org/support/topic/fatal-error-when-using-migration-file-extension/#post-16924496)
 * I see, I suspected it but couldn’t find anywhere confirmation of it, stating 
   this somewhere I think is necessary since currently the plugin link from the 
   admin plugins page only redirects to another page without information in this
   regard.

Viewing 5 replies - 1 through 5 (of 5 total)

The topic ‘Fatal Error when using Migration File Extension’ is closed to new replies.

 * ![](https://ps.w.org/all-in-one-wp-migration/assets/icon-256x256.png?rev=2458334)
 * [All-in-One WP Migration and Backup](https://wordpress.org/plugins/all-in-one-wp-migration/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/all-in-one-wp-migration/#faq)
 * [Support Threads](https://wordpress.org/support/plugin/all-in-one-wp-migration/)
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 * [Unresolved Topics](https://wordpress.org/support/plugin/all-in-one-wp-migration/unresolved/)
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 * 5 replies
 * 3 participants
 * Last reply from: [snippet24](https://wordpress.org/support/users/snippet24/)
 * Last activity: [2 years, 10 months ago](https://wordpress.org/support/topic/fatal-error-when-using-migration-file-extension/#post-16924496)
 * Status: resolved