Cannot load OCI DLL: oci.dll (4334917)

When trying to connect getting error : "Cannot load OCI DLL: oci.dll"
 

As per release notes:

OCI error displayed when the Oracle client setting is changed in a connection profile: In some circumstances, changing the Oracle client setting within a profile can cause problems with loading the correct OCI.DLL. To resolve this issue, set the Oracle client global option to the desired Oracle client by specifying the specific client to use when connecting in Oracle Home: parameter for a connection property | Details tab. See screenshots in attachment.

The most likely reason for that error is that you are missing 32 bit Oracle client on the PC where you have your Spotlight installed. if you have 64 bit Oracle client , you can still install 32 bit Oracle as well and select Spotlight's connection's properties from Default to the 32 bit Oracle Home if the default is not 32 bit.
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Also see SOL69734.