Error
During startup of the Oracle database getting the following error:

startup
ORACLE instance started.
Total System Global Area 1610609744 bytes
Fixed Size                  9028688 bytes
Variable Size            1258291200 bytes
Database Buffers          335544320 bytes
Redo Buffers                7745536 bytes
Database mounted.
ORA-03113: end-of-file on communication channel
Process ID: 20876
Session ID: 296 Serial number: 6999

On Checking the alert log, Getting the following error:

Errors in file C:\ORACLE\diag\rdbms\xe\xe\trace\xe_lgwr_16748.trc:
ORA-00313: open failed for members of log group 5 of thread 1
ORA-00312: online log 5 thread 1: 'C:\ORACLE\ORADATA\XE\REDO05.LOG'
ORA-27041: unable to open file
OSD-04002: unable to open file
O/S-Error: (OS 2) The system cannot find the file specified.

Solution: Clear the redo log group which causing the problem. Alert log file show us the log group 5 is causing problem.

1. Connect with new session and open Database in mount stage

sqlplus / as sysdba

startup mount
ORACLE instance started.
Total System Global Area 1610609744 bytes
Fixed Size                  9028688 bytes
Variable Size            1258291200 bytes
Database Buffers          335544320 bytes
Redo Buffers                7745536 bytes
Database mounted.

2. Run the Clear archive log command.

SQL> alter  database clear  logfile group 5;
Database altered.
--If the corrupt redo log file has not been archived, use the UNARCHIVED keyword in the statement
alter database clear unarchived logfile group 5;

3. Open the Database.

SQL> alter database open;
Database altered.