use my ADO.au3 UDF and this function: _ADO_GetProvidersList() And show which provider names are avalaible in your system. And second thoughts:   .ConnectionString =("Provider='OraOLEDB.Oracle';Data Source='DVA';User Id='system';Password='mypass';") this looks wrong for me. Quick look here: https://www.connectionstrings.com/oracle-provider-for-ole-db-oraoledb/ And here is my guess:   .ConnectionString ="Provider=OraOLEDB.Oracle;Data Source=DVA;U