Got this error during the upgrading the database to 184.108.40.206 (DBUA step 2-3) :
The Upgrade Assistant failed in bringing up the database ....
Here the action for fix the issue.
1. Remove all spfile from Old ORACLE HOME/dbs (copy them or change there names).
2. Remove all from $ORACLE_BASE/cfgtoollogs/dbua
*** ORACLE_BASE - base directory given by you during software installation
3. Re-run the DBUA: cd $ORACLE_HOME/bin; ./dbua
Good Luck ...