The migration is a very detailed process.
You must follow the migration procedure exactly as it is written.
If migration has failed then the previous DSM 6 information still exists in the Plex share. It cannot be manually migrated.
The migration log shown above is incomplete.
The migration procedure will take quite a long time to perform – depending on how much media you have. On a X86 processor, it might require 1-2 hours to complete and cannot be interrupted.