Here are some notes and comments on the topic. Additional entries will be added as new points of interest or issues arise that are deemed worth sharing.
Unable to create restore point
Try using a non-default local storage location. Example:
Name: local-non-default Notes: Necessary for restore points to work on some servers. Storage Folder: /[root path]/backups/duplicator
Cannot log in after migration
If unable to login after site duplication:
- Check the plugin devs recommendations
- Clear browser cookies for the original site: I’ve experienced a conflict with a lasting auth cookie.
Root folder permission error (Pro version)
If WordPress is installed in a subdirectory, try setting ABSPATH as root path: Duplicator Pro > Settings > Packages > Advanced Settings.
Subdirectory install ignored / Adding everything inside root folder (Pro version)
Try setting ABSPATH as root path: Duplicator Pro > Settings > Packages > Advanced Settings.
Ajax error during package building
Message: „Communication to AJAX is blocked.“
x) Disable maintenance mode (e.g. „All in One WP Security and Firewall“).
x) Make sure wp-config.php doesn’t contain one of these:
define('ALTERNATE_WP_CRON', true);define('DISABLE_WP_CRON', true);
Unable to delete Packages
Try deleting packages one by one.
Interrupt in Build Package – no timeout
On SiteGround hosting servers add to htaccess:
<IfModule mod_security.c> SecFilterRemove 001838 </IfModule>
Undefined error during backup creation
Add folder and plugin filters, especially for caching and security plugins (e.g. /plugins/wordfence/lib).
Binary Code in installer.php file
Download dirctly from snapshots folder. Probably the web server is trying to change the mime type.
Make sure wp-config is inside the package (not just a redirect).
Duplicator Pro 502 Bad Gateway error and allowed memory size error
For SiteGround Hosting accounts:
It appears that the pro version is trying to allocate way too much PHP memory. This issue is interfering with the normal work of the per-user Apache which is responsible for the UltraFast PHP that can be set on a per site basis (Site Tools > Devs > PHP Manager). If the website ist set to use Standart PHP the errors disappear.