User merge failed, corrupted database entries due to third party plugin

[IAmGav (Gavin Perch)]

this might help

Change ownership of all posts by a specific user

This guide outlines the process to change the ownership of all posts by a specific user. This task requires console access. Required user level: Server administrator with SSH access In Discourse, there may be situations where you need to change the ownership of all posts by a specific user. This guide provides the steps for achieving this on self-hosted Discourse instances. If you’re using Discourse hosting, please contact the support team at team@discourse.o…