Cannot load OCI: C:\Oracle\product\12.2.0\client_1\BIN\OCI.dll

Well that simplifies things. Toad 13.1 should work with that client.

I wonder if something is off in the registry. I have done the following with success when I've had client problems.

Note: Before doing the following, see if you have a file called oraaccess.xml in the same location as your sqlnet.ora and tnsnames.ora files. This file does not need to be present, but if it is present, any mistakes in the file (or an empty file) will cause the dreaded "Can't initialize OCI. Error -1" error.

  1. Use the deinstaller to deinstall the 12.2 client
  2. Make sure there is no trace of any oracle client on your computer:
  • Hard drive (check where it was installed, and also look under Program Files and Program Files (x86)
  • System path
  • Registry: If either of these are still present after deinstall, make sure all clients are deinstalled. Then remove these registry hives if they still exist.
  • Environment Variables: Any oracle-related environment variables (except TNS_ADMIN) should be removed.
  1. Reboot
  2. Reinstall oracle client.
    If you have 64 bit Toad, you must use 64 bit Oracle client.
    If you have 32 bit Toad, you must use 32 bit Oracle client.