ORA-00980: synonym translation is no longer valid tips

Oracle MOSC has great notes regarding ORA-00980 in which users have found that the DB crashes in startup in Enterprise versions 9.2-9.2 on any platform.  This instance of ORA-00980 typically either occurs along with ORA-01092 when the startup crashes, or just ahead of the finishing clean shut down (even if the database had previously been running properly).  ORA-00980 is associated with dropped sys user dual table which throws ORA-00980 upon database shutdown or database startup. 

Startup failure with ORA-00980 and ORA-01092 appears as follows:

===========================================
SQL> startup;
ORACLE instance started.

Total System Global Area 110173996 bytes
Fixed Size 454444 bytes
Variable Size 92274688 bytes
Database Buffers 16777216 bytes
Redo Buffers 667648 bytes
Database mounted.
ORA-01092: ORACLE instance terminated. Disconnection forced
==========================================

Upon setting the Errorstack in init.ora to find the cause of the ORA-00980, the errorstack report shows that ORA-00980 is involved in a problematic SQL:

==========================================
*** 2004-08-18 17:32:55.837
ksedmp: internal or fatal error
ORA-00980: synonym translation is no longer valid
Current SQL statement for this session:
select 1 from dual where exists (select 1 from system.repcat$_repprop prop
where prop.type in (-1,2,9,-4) and prop.how in (1,3))
==========================================

To resolve ORA-00980, note that ORA-00980 is causing the database shutdown because it is occurring during the db opening.  This being, to resolve ORA-00980, you would need to make a Dual Table, when not in the mount stage as a workaround.  First, put replication_dependency_tracking = FALSE in init.ora and startup the database. Next, make a Dual Public Synonym and Dual Table, such as:

CREATE TABLE "SYS"."DUAL"
( "DUMMY" VARCHAR2(1)
) PCTFREE 10 PCTUSED 4;
Insert Into Dual Values ('X');
Commit;
Grant Select On Dual To Public;

Lastly, take out the parameter above, and try restarting your database.  However, while resolving ORA-00980, remember that Dual Tables shouldn't ever be dropped, or serious problems can occur.

Oracle docs also has more information on ORA-00980 regarding invalid synonyms.  Here, they reveal that:

"ORA-00980: synonym translation is no longer valid" is a common error encountered in a development environment. This can happen for many reasons. Some of them are
1. You created a synonym on non-existing object by mistake. For example, you created a synonym on SCOTT.DEPT where either the SCOTT schema in not present or the DEPT table is missing.
2. You dropped an object but you did not drop the synonyms referencing the object.
3. You dropped a user, but you did not drop synonyms referencing the objects owned by that user.

Keep in mind when reviewing your ORA-00980 situation that as objects become dropped the synonyms aren't.