Toad for Oracle -- OCI cant initialize error

Normally, I dont write about Toad.. Actually I dont write about any client tools, but this time I m writing for Toad because I like to write the undocumented things :)

The error is the famous "OCI cant initialize" error. Oracle Call Interface (OCI) stands for the Oracle Call Interface , and it is the comprehensive, high performance, native C language interface to Oracle Database. 

Altough the cause seems to be realted with a problem in OCI initialization, it is actually a result..

The error is encountered when we try to connect to a database. any database actually.
The error may be encountered one day, without any reason.
OCI error may be just for some users.. Even if all the users are using a single toad binary through the Windows Terminal Server, this error may be seen only by some users..

The solution is to delete the directory named AppData\Roaming\Quest Software\Toad for Oracle for the problematic users.. Note that : if you delete this directory your license info, your password and your connection information will be deleted too.
An alternative may be to delete the directory of the problematic user and copy the same directory from another user.. Like copying C:\Users\erman\AppData\Roaming\Quest Software\ to C:\Users\ali\AppData\Roaming\Quest Software

AppData\Roaming in Windows is where programs on your machine store data that is specific to your user account. The folder is normally hidden, you need to display the hidden files to make operations on it.

So the cause must be something like a logical corruption or a security problem introduced with a new configuration in the files of Toad located in the Roamin folder.

Anayways, you dont need to reinstall Toad if you get this OCI cant initialize error...Try the solution that I have mentioned above in the first place :)