The 32-bit ODBC Administrator is found at %systemdrive%/Windows/
It can be tempting -- and in some ways useful -- to use identical names for 32-bit and 64-bit DSNs. This controls 64-bit ODBC drivers, which are required by 64-bit client applications. (The 64-bit ODBC Administrator can also be accessed through the Control Panels interface, as the Data Sources (ODBC) control Likewise, the 64-bit Administrator, and all 64-bit ODBC applications (typically installed to %systemdrive%/Program Files/), will list 32-bit User DSNs (that is, DSNs based on 32-bit ODBC drivers) -- even though these This is fine -- but you then need to be very careful to keep the 32-bit and 64-bit DSN configurations in sync, as different output resulting from different configurations can lead https://support.microsoft.com/en-us/help/942976/odbc-administrator-tool-displays-both-the-32-bit-and-the-64-bit-user-dsns-in-a-64-bit-version-of-windows
This controls 32-bit ODBC drivers, which are required by 32-bit client applications. (The 32-bit ODBC Administrator cannot be accessed through the Control Panels interface; the Data Sources (ODBC) control panel is Related Special Considerations when using Microsoft SQL Server as the Data Consumer, on 64-bit Windows Referenced by... © OpenLink Software 2016. For this reason among others, we strongly advise using only System DSNs in 64-bit environments.
System DSNs will only be seen by the applications and tools which can use them -- 32-bit DSNs for 32-bit applications, and 64-bit DSNs for 64-bit applications.