Oracle: Oracle Uninstall

Sometimes working with Oracle can be a big pain in the backside, especially when trying to uninstall and ensuring that all components have been removed. Case in point, we had an employee whose desktop application failed to connect to the backend database correctly after having her machine reformatted and “re-imaged”. The image file came pre-installed with an Oracle 8.0.5 client. Kind of made things difficult to connect to an Oracle 9i Server. Rather than playing around with the TSNNAMES.ORA file to resolve this, I opted to upgrade the system in question to Oracle 9i. This is where the “Help Desk” failed. First, since they couldn’t find the Uninstall option in Add/Remove programs, they didn’t uninstall the old version. Then, they just applied another “image” of Oracle 9, which was corrupt. They didn’t bother removing the old Oracle from the PATH statement, set the 9i version in the HOME setting, so of course, this didn’t work. The system could not connect through ODBC, testing through a UDL file, or through the desktop client. Sql-Plus worked, but only with version 9. Luckily I was able to get this resolved. Here are the steps I followed.

• Uninstalled version 8.0.5 via the Oracle Universal Installer.


• Uninstalled the Corrupt 9i via the Universal Installer.


• Removed the old Oracle 8.0.5 entry from the path statement (C:\orant\bin).


• Backed up and deleted the C:\OraNT directory.


• Backed up and deleted the C:\Oracle directory.


• Removed the following registry keys (Note, * are wildcards):


• Hkcu/Software/Oracle


• Hklm/Software/Oracle


• Hklm/Software/odbc/Microsoft/ODBC for Oracle


• Hklm/software/odbc/odbcinst.ini/Oracle*


• Hkey/Classes/root/(ora*, orcl*, oradc*, orammc*, oraole*, oraperf*)


• Hkusers/software/oracle


• Hkusers/s-(long number here)/Software/Oracle


• Hklm/SYSTEM/ControlSet00*/ Services/ (Oracle*)


• Hklm/SYSTEM/ CurrentControlSet/ Services/ (Oracle*)


• Reinstalled Oracle 9i Client fresh from CD.

And that resolved the connectivity issues.