Uninstall Oracle Client Software

by Snehashish Ghosh


Windows Server 2008 R2 64 bit machine requires clean deinstallation of Oracle database 11g 32 bit client to be uninstalled.

Due to corrupted Oracle Client Installation clean deinstall and re-install is required.


1. Find ODBC Data Source Administration Program for 32 bit in a 64 Bit Windows OS



In a 64 bit Windows machine the default ODBC Administrator contains drivers from only 64 bit Software.
So if we install 32 bit Oracle Client Software it will not be shown as a valid driver in User DSN and System DSN in the default ODBC Administrator.

The 32 bit driver is avilable in the 32 bit version of the ODBC Administrator.

32 bit version of ODBC Administrator in Windows Server 2008 R2 64 bit Os can be found in the following location:



Create a desktop shortcut of the above odbcad32.exe so that it is readily available.

It will show the Oracle 11g Client Driver in System DSN or User DSN.












The 64 bit version of ODBC Administrator does not have the Oracle Client Driver driver.



2. Deinstall the Oracle 11g client using deinstall.bat utility

We cannot install the Oracle 11g client using Oracle Universal Installer (OUI) like previous versions of Oracle.

Attempt to uninstall Oracle 11g client using OUI will throw following error:










So we need to use the deinstall binary supplied by Oracle under Oracle_Client_Home\deinstall

i) Open a command prompt

ii) navigate to Oracle_Client_Home\deinstall

iii) execute deinstall.bat utility










iv) write y then press enter

The following Windows and .NET products will be deconfigured from the Oracle hom
e : asp.net,odp.net,ntoledb,oo4o
Do you want to continue (y – yes, n – no)? [n]: y








Failed to delete directory ‘E:\oracle’ on the local node.
Oracle Universal Installer cleanup completed with errors.

Oracle install successfully cleaned up the temporary directories.\

You might receive the above error/warning messages which can be dealt with using the following steps:

iv) Delete the root folder of Oracle Client Installation, if it throws error saying that some .dll files are still in use then do one of the following:

i) Restart the machine which will free up the .dll file in use and the Oracle Client Installation directory can be removed.

ii) Use the Unlocker utility avilable for free in the following link and delete the .dll in use or the entire ORacle Client Installation Directory. http://unlocker.en.softonic.com/

iii) Use Process Explorer to find out the processes using the .dll file and individually kill those processes to free up the dll in use. Process Explorer is available here : http://technet.microsoft.com/en-in/sysinternals/bb896653.aspx

3. After using Oracle supplied deinstaller utility it is found that the Ora_Client11g_home1 driver is still present in the ODBC Administrator causing frustation to the person who have done uninstallation. Some time this scenario can surface only in Production Environment causing agony and serious tension to all the stakeholders involved. No Worry !!!!

The solution is as follows:

Clean Windows Registry to get rid of the Ora_Client11g_home1 driver:

3.1 Open regedit.exe












In the Right Pane you will see the Oracle in OraClient11g_home1 driver. Press Delete to remove this driver for ever.









voi·la the stubborn OraClient11g_home1 driver is removed from the ODBC Administrator Driver list also.














Although the deinstall utility has achieved to automate most of the manual Oracle Client Software Removal Steps like deleting the Oracle Client Installation Folder, Delete the Registry Entries from HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\ORACLE, Delete the Entries from C:\Program Files (x86)\Oracle\Inventory, it is not able to remove the driver information from Windows Registry causing confusion. Hope in next versions of Oracle deinstall the issue will be fixed and Oracle  deinstaller will have capability to remove the driver entry in Windows Registry as well.

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