I am using 64 bits Windows 7.

Oracle Development Tool: SQL Navigator 5.5 was installed on my computer. When I try to start the program I get this error:

"Unhandled Exception at startup - Cannot find OCI DLL: oci.dll"

Then I get this error:

"Access violation at address 0101916B in module 'SQLNav5.exe'. Read of address 00000000"

and then the program is terminatied.

Any ideas what is the problem?

Update: I am trying to install Oracle client - sql navigator - not sure if the server is 64 bits or not.


Have you installed any Oracle client software yet?


If you have installed the Oracle Client, what version did you install (64bit or 32bit)?

If you installed the 64bit Oracle Client to match your shiny 64bit OS there is a high chance that SQL Navigator was linked against the 32bit Oracle Client.

It won't be able to load the 64bit oci DLLs, hense the error you see.

For 64bit client machines I'd recommend using the 32bit Oracle Client until more applications start linking to the 64bit Oracle libraries.

You can still talk to 64bit databases just fine.


Make sure you have at least one version of Oracle Client installed.

  1. First un-install SQL Navigator
  2. System reboot
  3. Install SQL Navigator
  4. Find the location of OCI.dll (Windows+F on XP/7/Vista)
  5. Copy that OCI.dll and paste it in your set up folder of SQL NAvigator, most probably "C:\Program Files\Quest Software\SQL Navigator 5.5"
  6. You may still get some error like "Can't initialise OCI.dll-Error 1". Press OK
  7. Also click on OK if any other messages prompt on the screen.
  8. Test using connecting to any database you have known.

Run Sqlnav5.exe as administrator

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