I have a 32 Bit and 64 Bit "SYSTEM ODBC".... When in Alteryx under Manage In-DB Connections.....
Data Source: Microsoft SQL Server..
Connection Type: I see only File and User.... I DO NOT see System
We have 2 other PC's that are set up the same way and they see their System DSN connections.
Running Version 2019.4.8.22007