Thanks to one and all for helping me out on this issue. I'm trying out the option of copying all the files from host1(9ir2) to host2(10gr1) and then upgrade the database with dbua. After I bring the database up with "startup upgrade", I invoke dbua and receive the following error:ORA 00600 Internal error code, arguments: [17069], [0x53250820], [], [], [], [], [], [] I checked the udump tace file and it has call stack trace, binary stack dump, framedetails ...etc. All of them are in hexadecimal. What I did: I just exported the ORACLE_SID=catdb Initially dbua did not pickup the open catdb database for upgrade on the first screen. Hence I added catdb to /etc/oratab and dbua picked it up for upgrade and then giving me the oracle internal error. /etc/oratab: orams:/u01/oracle/app/product/10.1.0/Db_1:N catdb:/u01/oracle/app/product/10.1.0/Db_1:N Since my control file will be looking for files in the same setup as in 9ir2 host1, I replicated the same directory settings (only few) in 10gr1 host2. Settings below are from host2. [oracle@OEL5 ~]$ ls -l /opt/oracle total 12 drwxr-xr-x 3 oracle oinstall 4096 Aug 11 11:20 admin drwxr-xr-x 3 oracle oinstall 4096 Aug 11 11:13 oradata drwxr-xr-x 3 oracle oinstall 4096 Aug 11 11:00 product admin contains directories for trace oradata contains datafiles and product contains directory 9.2.0 which contains dbs directory that contains initcatdb.ora, orapwcatdb, spfilecatdb.ora (all three files were copied to 10gr1 directory). Any ideas on how to proceed??????? Thanks in advance...........