After importing Knowledge [kb_knowledge] records into an instance, the article records are no longer editable.
With the introduction of the Knowledge Management Advanced [com.snc.knowledge_advanced] plugin, users have the ability to version knowledge articles.
This data is stored in the Knowledge Version [kb_version] table.
Release or Environment
If kb_knowledge records are imported from an instance that is running a release that does not support versioning or if the associated kb_version records are not imported as well, the kb_knowledge records cannot be checked out and edited.
Ensure that all relevant kb_version records are imported along with the kb_knowledge records. Alternatively, you can also run the Initialize Versions on Articles fix script to set the version. This script is included with the Knowledge Management Advanced plugin and can be accessed by selecting System Definition > Fix Scripts from the application navigator.