That message should list the other offending package: ucfr: Attempt from package samba-common to take /etc/samba/smb.conf away from package <MISSING>
You could take a look what currently owns /etc/samba/smb.conf with "dpkg -S /etc/samba/smb.conf".
Other than that - to continue to help we would need to understand how to reproduce this issue, so for now I can only mark it as incomplete.
That message should list the other offending package:
ucfr: Attempt from package samba-common to take /etc/samba/smb.conf away from package <MISSING>
You could take a look what currently owns /etc/samba/smb.conf with "dpkg -S /etc/samba/ smb.conf" .
Other than that - to continue to help we would need to understand how to reproduce this issue, so for now I can only mark it as incomplete.