Title: Error with 4.5.8
Last modified: May 4, 2026

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# Error with 4.5.8

 *  [Timothée Brosille](https://wordpress.org/support/users/spaceshipone/)
 * (@spaceshipone)
 * [1 week, 2 days ago](https://wordpress.org/support/topic/error-with-4-5-8/)
 * Hi,
 * I’m experiencing an issue after updating the Duplicate Page plugin from version
   4.5.7 to 4.5.8.
 * My site uses both Duplicate Page and the Sendify Campaign plugin. Since updating
   to 4.5.8, duplicating my campaigns no longer works. If I roll back to version
   4.5.7, everything works correctly again.
 * Here is the error message I’m getting:
 *     ```wp-block-code
       Uncaught Error: The script tried to modify a property on an incomplete object. Please ensure that the class definition "stdClass" of the object you are trying to operate on was loaded before unserialize() gets called or provide an autoloader to load the class definition in /wp-includes/formatting.php:5157Stack trace: 0 /wp-includes/formatting.php(5152): map_deep() 1 /wp-includes/formatting.php(5152): map_deep() 2 /wp-includes/formatting.php(5152): map_deep() 3 /wp-includes/formatting.php(5152): map_deep() 4 /wp-includes/formatting.php(2861): map_deep() 5 /wp-includes/formatting.php(5814): stripslashes_deep() 6 /wp-includes/meta.php(63): wp_unslash() 7 /wp-includes/post.php(2658): add_metadata() 8 /wp-content/plugins/duplicate-page/duplicatepage.php(221): add_post_meta() 9 /wp-content/plugins/duplicate-page/duplicatepage.php(122): duplicate_page->duplicate_edit_post() 10 /wp-includes/class-wp-hook.php(341): duplicate_page->dt_duplicate_post_as_draft() 11 /wp-includes/class-wp-hook.php(365): WP_Hook->apply_filters() 12 /wp-includes/plugin.php(522): WP_Hook->do_action() 13 /wp-admin/admin.php(424): do_action() 14 {main}
       ```
   
 * It seems related to how metadata is handled during duplication, possibly involving
   serialized objects.
 * Could you please advise if this is a known issue in 4.5.8, or if there is a workaround
   or fix available?
 * Thank you for your help.

Viewing 1 replies (of 1 total)

 *  Plugin Support [Emma (Support Executive)](https://wordpress.org/support/users/emma1991/)
 * (@emma1991)
 * [1 week, 2 days ago](https://wordpress.org/support/topic/error-with-4-5-8/#post-18899007)
 * Hi [@spaceshipone](https://wordpress.org/support/users/spaceshipone/) ,
 * Thank you for sharing the detailed error log-this is incredibly helpful. Yes,
   this is a known issue that’s already been reported, and our team has identified
   and fixed the bug.
 * The patched update will be live later this week. Once it’s released, the issue
   will be fully resolved, and you’ll be able to update safely again.
 * In the meantime, staying on version 4.5.7 is completely safe while we roll out
   the fix.
 * Thank you for your patience and for helping us improve Duplicate Page.
 * Best regards,
   Duplicate Page Support

Viewing 1 replies (of 1 total)

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 * 1 reply
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 * Last reply from: [Emma (Support Executive)](https://wordpress.org/support/users/emma1991/)
 * Last activity: [1 week, 2 days ago](https://wordpress.org/support/topic/error-with-4-5-8/#post-18899007)
 * Status: not resolved