Delete all Custom Field entries assigned to posts that do not exist in the posts table.
Navigate to Settings -> Remove Unused CFs and delete all postmeta for non-existing posts.
- Upload the DX Remove Unused Custom Fields plugin to your blog and activate it.
- Go to Settings -> Remove Unused CFs
- Click ‘Delete’ to drop the unrelated fields.
- Is it permanently removing the data?
Yes, the data would be removed from the database so use at your own risk.