I'm pretty sure I have a good workaround if you plan to do an immediate restore after your backup.

Before running a gbak.exe backup do a

DROP ROLE RDB$ADMIN;
COMMIT;

When you restore, gbak.exe will recreate the RDB$ADMIN role.

It has worked for me every time.

--- In firebird-support@yahoogroups.com, "slalom91" <slalom91@...> wrote:
>
> When running the restore process on v2.5 I am receiving the following error:
>
> "attempt to store duplicate value (visible to active transactions) in unique index "RDB$INDEX_39"
>
> I have reviewed the RDB$INDICES table on the source database and this index refers to the RDB$ROLES table and specifically is the unique index on RDB$ROLE_NAME. Their is only one record in RDB$ROLES and it is the RDB$ADMIN role.
>
> Any ideas on how to address this issue?
>