user11262980 wrote:You have a backup or other process running that tries to access (and lock) database files while db instance is up.
This is an extract from alert_xe.log
Mon Nov 12 22:13:35 2012
Errors in file d:\data\p6\db\app\oracle\admin\xe\bdump\xe_ckpt_5856.trc:
ORA-00221: error on write to control file
ORA-00206: error in writing (block 3, # blocks 1) of control file
ORA-00202: control file: 'D:\DATA\P6\DB\ORADATA\XE\CONTROL.DBF'
ORA-27072: File I/O error
OSD-04008: WriteFile() failure, unable to write to file
O/S-Error: (OS 33) The process cannot access the file because another process has locked a portion of the file.
Mon Nov 12 22:13:35 2012Because control file could not be written to, CKPT has no alternative but to shut down to protect the database.
CKPT: terminating instance due to error 221