Ok so a colleague of mine manages a large number of Oracle 10g XE databases and one of them is failing to open this morning because of a corrupt SYSTEM tablespace. And unfortunately the backups for this database are gone as well. We do have some full database exports from a couple weeks ago so it is not a complete loss. Does anybody know of maybe some undocumented parameter or some way to recover from this database? Below is the alert log. ALTER DATABASE MOUNT Thu Aug 09 08:49:28 2012 Setting recovery target incarnation to 2 Thu Aug 09 08:49:28 2012 Successful mount of redo thread 1, with mount id 2672004948 Thu Aug 09 08:49:28 2012 Database mounted in Exclusive Mode Completed: ALTER DATABASE MOUNT Thu Aug 09 08:49:50 2012 alter database open upgrade Thu Aug 09 08:49:50 2012 Beginning crash recovery of 1 threads Thu Aug 09 08:49:50 2012 Started redo scan Thu Aug 09 08:49:50 2012 Completed redo scan 0 redo blocks read, 0 data blocks need recovery Thu Aug 09 08:49:50 2012 Started redo application at Thread 1: logseq 84298, block 3, scn 10745981851 Thu Aug 09 08:49:50 2012 Recovery of Online Redo Log: Thread 1 Group 4 Seq 84298 Reading mem 0 Mem# 0 errs 0: D:\DATA\ORACLE\ORADATA\XE\REDO04A.LOG Mem# 1 errs 0: D:\DATA\ORACLE\ORADATA\XE\REDO04B.LOG Thu Aug 09 08:49:50 2012 Completed redo application Thu Aug 09 08:49:50 2012 Completed crash recovery at Thread 1: logseq 84298, block 3, scn 10746001852 0 data blocks read, 0 data blocks written, 0 redo blocks read Thu Aug 09 08:49:51 2012 LGWR: STARTING ARCH PROCESSES ARC0 started with pid, OS id%24 Thu Aug 09 08:49:51 2012 ARC0: Archival started ARC1 started with pid , OS id)56 Thu Aug 09 08:49:52 2012 ARC1: Archival started LGWR: STARTING ARCH PROCESSES COMPLETE Thread 1 advanced to log sequence 84299 Thread 1 opened at log sequence 84299 Current log# 2 seq# 84299 mem# 0: D:\DATA\ORACLE\ORADATA\XE\REDO02A.LOG Current log# 2 seq# 84299 mem# 1: D:\DATA\ORACLE\ORADATA\XE\REDO02B.LOG Successful open of redo thread 1 Thu Aug 09 08:49:52 2012 ARC1: STARTING ARCH PROCESSES Thu Aug 09 08:49:52 2012 ARC0: Becoming the 'no FAL' ARCH ARC0: Becoming the 'no SRL' ARCH Thu Aug 09 08:49:52 2012 SMON: enabling cache recovery Thu Aug 09 08:49:52 2012 ARC2: Archival started Thu Aug 09 08:49:52 2012 ARC1: STARTING ARCH PROCESSES COMPLETE ARC1: Becoming the heartbeat ARCH ARC2 started with pid!, OS id916 Thu Aug 09 08:49:54 2012 Successfully onlined Undo Tablespace 1. Thu Aug 09 08:49:54 2012 SMON: enabling tx recovery Thu Aug 09 08:49:54 2012 Database Characterset is WE8MSWIN1252 Thu Aug 09 08:49:56 2012 Hex dump of (file 1, block 39) in trace file c:\oraclexe\app\oracle\admin\xe\bdump\xe_smon_876.trc Corrupt block relative dba: 0x00400027 (file 1, block 39) Bad check value found during buffer read Data in bad block: type: 6 format: 2 rdba: 0x00400027 last change scn: 0x0002.7fee0b69 seq: 0x1 flg: 0x06 spare1: 0x0 spare2: 0x0 spare3: 0x0 consistency value in tail: 0x0b690601 check value in block header: 0x8f6c computed block checksum: 0x1000 Reread of rdba: 0x00400027 (file 1, block 39) found same corrupted data Thu Aug 09 08:49:56 2012 Stopping background process MMNL Thu Aug 09 08:49:56 2012 Errors in file c:\oraclexe\app\oracle\admin\xe\bdump\xe_smon_876.trc: ORA-00604: error occurred at recursive SQL level 1 ORA-01578: ORACLE data block corrupted (file # 1, block # 39) ORA-01110: data file 1: 'D:\DATA\ORACLE\ORADATA\XE\SYSTEM.DBF' Thu Aug 09 08:49:57 2012 Stopping background process MMON Starting background process MMON Starting background process MMNL MMON started with pid, OS id12 Thu Aug 09 08:49:58 2012 ALTER SYSTEM enable restricted session; MMNL started with pid, OS id584 Thu Aug 09 08:49:58 2012 ALTER SYSTEM SET _system_trig_enabledúLSE SCOPE=MEMORY; Thu Aug 09 08:49:58 2012 ALTER SYSTEM SET aq_tm_processes=0 SCOPE=MEMORY; Thu Aug 09 08:49:58 2012 Errors in file c:\oraclexe\app\oracle\admin\xe\udump\xe_ora_324.trc: ORA-00604: error occurred at recursive SQL level 1 ORA-01578: ORACLE data block corrupted (file # 1, block # 39) ORA-01110: data file 1: 'D:\DATA\ORACLE\ORADATA\XE\SYSTEM.DBF' Thu Aug 09 08:49:58 2012 Error 604 happened during db open, shutting down database USER: terminating instance due to error 604 Thu Aug 09 08:49:59 2012 Errors in file c:\oraclexe\app\oracle\admin\xe\bdump\xe_pmon_3120.trc: ORA-00604: error occurred at recursive SQL level Thu Aug 09 08:49:59 2012 Errors in file c:\oraclexe\app\oracle\admin\xe\bdump\xe_psp0_3444.trc: ORA-00604: error occurred at recursive SQL level Thu Aug 09 08:49:59 2012 Errors in file c:\oraclexe\app\oracle\admin\xe\bdump\xe_mman_2592.trc: ORA-00604: error occurred at recursive SQL level Thu Aug 09 08:49:59 2012 Errors in file c:\oraclexe\app\oracle\admin\xe\bdump\xe_dbw0_932.trc: ORA-00604: error occurred at recursive SQL level Thu Aug 09 08:49:59 2012 Errors in file c:\oraclexe\app\oracle\admin\xe\bdump\xe_ckpt_1156.trc: ORA-00604: error occurred at recursive SQL level Thu Aug 09 08:50:00 2012 Errors in file c:\oraclexe\app\oracle\admin\xe\bdump\xe_lgwr_1508.trc: ORA-00604: error occurred at recursive SQL level Thu Aug 09 08:50:00 2012 Errors in file c:\oraclexe\app\oracle\admin\xe\bdump\xe_reco_2700.trc: ORA-00604: error occurred at recursive SQL level Thu Aug 09 08:50:00 2012 Errors in file c:\oraclexe\app\oracle\admin\xe\bdump\xe_smon_876.trc: ORA-00604: error occurred at recursive SQL level Jeff -- //www.freelists.org/webpage/oracle-l