How to uninstall Oracle

Part of our "How do I do that in Oracle?" series, this tip, compiled largely of advice from our expert Oracle DBAs, explains in detail how to uninstall Oracle software from your system.

Part of our "How do I do that in Oracle?" series, this tip explains in detail how to uninstall Oracle software...

(8i, 9i or 10g) from your system. This tip is compiled largely of advice from our expert Oracle DBAs including installation expert Maria Anderson and database design and backup and recovery expert Brian Peasland.

From "Uninstalling Oracle 8":

To remove Oracle components from a Windows machine, first take a full system backup of your server! You could try uninstalling Oracle via the Installer but if this does not work, follow this manual procedure:

  • Ensure you are logged in as a user with Administrator privileges.
  • Stop all Oracle services (if any are running).
  • Remove the Oracle entries in the Windows registry.
  • Clean up the environment settings.
  • Delete the software and icons.
  • Empty the recycle bin.
  • Reboot your computer.
  • Optionally, if you are on Windows 2000 or XP run the System Defragmenter.

Detailed steps can be found in the Oracle Installation Guide for Windows on Oracle's Technology Network.

From "Uninstalling Oracle9i":

To uninstall Oracle, follow these steps:

  1. Go to Services and make sure that all Oracle services are stopped.
  2. Invoke the Oracle Universal Installer (OUI) to uninstall the software.
  3. Go to Start->Run and type 'regedit' to invoke the registry editor.
  4. Navigate to HKEY_LOCAL_MACHINESoftware and delete the Oracle folder.
  5. Right click on My Computer and select Properties. Click to access the Environment Variables. Find the PATH environment variable and edit it to remove any occurences of Oracle directories.
  6. Using Explorer, remove any remaining Oracle directories, notably the ORACLE_HOME and C:Program FilesOracle. If there are files you cannot remove, reboot your machine and retry the delete operation.

You should now have a clean machine that you can reinstall Oracle on.

From "Removing Oracle9i and reinstalling it": A user wrote, "I want to completely remove Oracle 9i from my computer and install it again. How to remove it from the REGEDIT?" Maria Anderson responded:

Did you uninstall the Oracle software using the Oracle Universal Installer? When using the OUI, it will generally clean up all required registry entries for you. If you want to remove the Oracle software manually, there is a very good article on Metalink (Doc ID #124353.1) which describes in detail how to manually remove Oracle components on the Windows platform. At a high level, the steps you need to take to uninstall Oracle are as follows:

  • Ensure you are logged in as a user with Administrator privileges.
  • Stop all Oracle services (if any are running).
  • If possible, remove the Oracle software by invoking the Oracle Universal Installer (OUI) and remove the software.
  • Remove the entries in the Windows registry.
  • Clean up environment settings.
  • If you could not use the OUI to uninstall the software, delete the software and icons at this point.
  • Empty the recycle bin.

One word of caution is to be very careful editing registry entries.

If, after de-installation, Oracle services are still showing up in the administrative tasks, follow this advice (from "Uninstalled services still showing up in Win2000"):

You'll have to edit the registry to delete all existing ORACLE services. First make sure all services are stopped, then use the Registry Editor (REGEDIT) and remove any folders in the locations listed below that have the service name you wish to remove.


There are typically two control sets, ControlSet001 and ControlSet002. But, your environment may be different. Therefore, check all of your control sets, signified by the X, that exist in your registry. Delete any folders in the above locations with the name OracleXXX.

Did you erase more registry keys than necessary? The best way to uninstall Oracle is to use the Oracle Universal Installer (OUI) because it clears out relevant registry entries, along with the inventory and operating system files. Start the OUI and uninstall all Oracle products, then try the installation again. (From "Erased too many registry keys with deinstall")

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