Using Oracle’s built-in uninstaller cannot completely remove Oracle, potentially leaving issues for the next installation. So how can we completely uninstall Oracle? The answer is to manually clean the registry.
Steps to completely uninstall Oracle
1. Start > Settings > Control Panel > Administrative Tools > Services
Stop all Oracle services.
OracleOraDb11g_home1TNSListener: Specifically supports remote access to the Oracle database (for Java applications accessing Oracle, it takes about 1 second to start this service each time).
OracleServiceXE: “XE” is the database name. This is the core Oracle service, related to the operation of the entire Oracle database. This service must be running, as stopping it will prevent connection to the Oracle server. It takes about 2 minutes to start this service. If set to automatic, you’ll notice your computer will be slower by about 2 minutes compared to before.
2. (Optional) Start > Programs > Oracle – OraDb11g_home1 > Oracle Uninstall Products > Universal Installer
Uninstall all Oracle products, but the Universal Installer itself cannot be deleted. (If step 2 fails, skip to step 3. Most of the time, step 2 will fail.)
3. Run regedit, go to HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE, and press the Del key to delete this entry.
4. Run regedit, and delete all Oracle entries from the following locations:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services (delete all Oracle entries under this path)
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\Services (delete all Oracle entries under this path)
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Services (delete all Oracle entries under this path)
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services (delete all Oracle entries under this path)
5. Run regedit, go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Eventlog\Application, and delete all Oracle entries.
6. Start > Settings > Control Panel > System > Advanced > Environment Variables
Delete any Oracle-related settings from the CLASSPATH and PATH environment variables.
7. Delete all Oracle-related groups and icons from the desktop, STARTUP group, and program menu.
8. Delete the e:/oracleDB directory.
9. Restart the computer. The Oracle directory can only be completely deleted after restarting.
10. Delete Oracle-related files by navigating to the default directory where Oracle is installed, typically C:\Oracle, and delete this directory along with all subdirectories. Also, delete any Oracle-related files from the Windows directory (usually C:\WINDOWS).
11. In the Run box, type win.ini and press Enter. If the [ORACLE] section exists in the WIN.INI file, delete that section.
12. If necessary, delete all Oracle-related ODBC DSN entries.
13. Open the Event Viewer and delete any Oracle-related logs.
Note:
If there are some DLL files that cannot be deleted, don’t worry. Simply restart the computer and begin the new installation. During the installation, choose a new directory, and after installation and restart, the old directory and files can be deleted.
