Toad World® Forums

Unable to login or connect with Toad

Hi All,

While trying to connect toad i am getting below error

Cannot load OCI DLL: C:\Program Files\Oracle\óraclient\instantclient_10_2\oci.dll

Windows 10 64 bit
Toad for oracle database login version (32 bit)
instantclient-basic-win32- --installed
Microsoft Visual C++ 2010 x64 Redistributable Setup----installed

Help me to resolve issue

Bharathi Chitrarasan

You must use the same bitness for Toad and Oracle Client. Mixing 32 and 64 bit doesn't work.


Hi Norm,

I have removed 64 bit instant client and now I have only 32 bit instant client the same given in environment variable.

After setting temp path to instant client 32 bit while connecting toad it throws ORA-06413: Connection not open

With old oracle versions, if your client app (in this case Toad) is installed into a folder with parenthesis (such as c:\Program Files (x86)\Quest Software\Toad) then this error can occur.

You can solve it by uninstalling Toad and then reinstalling it to a path with no parenthesis.

Hi John,

Yes it was installed in path c:\Program Files (x86)\Quest Software\Toad for oracle and now i have uninstalled and installed in path c:\Program Files \Quest Software\Toad for oracle. Still facing same issue "ORA-06413: Connection not open"

I downloaded an Oracle client version 10.1 32 bit and was able to reproduce the same problem as you. I thought your path, with the ó in óraclient may have been a problem but even when I changed that the problem was not solved.

I think there is some incompatibility between the 10.1 client and Toad 9.7.

I deleted the 10.1 client, installed a 10.2 client, and was able to connect successfully with Toad 9.7.

This is the client that I installed:

Please do the following to solve your problem:

  1. delete all installed Oracle clients.
  2. make sure there is no trace of any oracle client on hard drive, system path, or registry - specifically HKLM\SOFTWARE\ can just delete that node after deinstall. Also check HTML\SOFTWARE\Wow6432Node\ORACLE for good measure)
  3. reboot
  4. install the 10.2 oracle client to a simple path with no spaces and only ascii characters.
    I suggest C:\Oracle\Client
  5. update your path variable to include the location of oci.dll
  6. If you are using a TNSNames file, put it in c:\Oracle\TNSAdmin
  7. Update or create your TNS_ADMIN variable to c:\Oracle\TNSAdmin

That should get you going.