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Tuesday, May 4, 2010

Solving the TOra 2.1.1 Missing Error Description

I recently got rid of my old TOra installation and replaced it with the newer TOra 2.1.1.  Every time I tried to connect to an Oracle database, I get a "Unable to connect to the database. ORA-27749784 missing error description." as shown below.

Delete the oci.dll in your TOra directory e.g. C:\Program Files\TOra.

I have Oracle 10g client installed on my desktop.  I believe TOra references the oci.dll in the Oracle Client's bin directory e.g. C:\oracle\product\10.2.0\client_1\BIN.  If you copy the oci.dll in this bin directory to the TOra directory, it will work the same way.

About TOra
TOra is an open-source multi-platform database management GUI that supports accessing most of the common database platforms in use, including Oracle, MySQL, and Postgres, as well as limited support for any target that can be accessed through Qt's ODBC support. TOra has been built for various Linux distributions, Mac OS X, MS Windows, and UNIX platforms [source:].


  1. Thanks! I renamed oci.dll to oci.dll.old and I am connected to Oracle.

  2. I am having the same issue, I renamed the old oci.dll file -didnt work

    I copied the oci.dll file from the oracle instant client directory to the Tora insall directory - didnt work.

    error message:
    ORA-12170 TNS: Connect timeout occured

    Any ideas?

  3. Check how many instances of oci.dll you have on your PC. Check your PATH environment variable to see which one gets read first. Then you have to figure out which version works then move the directory to the beginning of your PATH environment variable. Good luck!

  4. Thanks.. This helped.

  5. Thanks for you help.