Can't Initialize OCI.Error -1 when trying to log in to toad

[JohnDorlon]

Does this help?

Can't initialize oci. Error -1

Do you have DynaTrace installed on the same PC? If so, there is an incompatibility between DynaTrace and 64 bit Toad on Windows 10 or Server 2016. This will be fixed in the version after 14.0. You can work around it by using the 32 bit version of Toad. When you say "can toad and oracle be installed on same PC", are you referring to oracle server or client? The answer is "yes" either way, but I'm not clear on your config.