Oci.dll errors are caused by situations that lead to the removal or corruption of the oci DLL file. This is an API used with Oracle software and stands for Oracle Call Interface.

In some cases, oci.dll errors can indicate a registry problem, a virus or malware issue, or even a hardware failure.

Recover oci.dll from the Recycle Bin. The simplest possible cause of a "missing" oci.dll file is that you accidentally deleted it.

If you suspect this and you're sure the file was working fine when you deleted it (i.e., it wasn't malicious), you may be able to recover it with a free file recovery program.