Where are ODBC Machine DSN settings stored in Windows? - ms-access

Question

In my Access database, I reference the DSN, "mydatasourcename" to connect to an online MySQL database. It is a machine DSN. Somehow through the course of editing my config files, a phantom DSN was created. This DSN is now out of date and I need to update it with the new hostname (after having migrated the MySQL Server). But the config file is nowhere to be found. It does not show up in either 32-bit or 64-bit "ODBC Data Sources" forms. I have searched "mydatasourcename" in the Registry Editor and it is not there either. Mysteriously, when I open an Access linked table referencing "mydatasourcename" it opens a MySQL ODBC Connector dialogue with the old connection information in it. How is it doing this? Where is it getting the connection string information? To answer this question, I am requesting a list of the places the ODBC driver looks for configuration files and how to access them so I can delete the old configuration file. I am using MySQL ODBC Connector 8.0.16. Thank you.
EDIT: The connection string found in my linked table is definitely looking outside of Access for connection info based on the fact that is referencing a DSN. The connection string in one of my linked tables is the following: "ODBC;DSN=mydatasourcename;;TABLE=qrychemigationapplications_materialsrequired1"

Answer 1

On Windows, ODBC DSN information is stored in the Windows Registry. System DSNs can be found in the registry keys
DSNs for 64-bit drivers: HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\ODBC.INI
DSNs for 32-bit drivers: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\ODBC\ODBC.INI
and User DSNs can be found in
HKEY_CURRENT_USER\SOFTWARE\ODBC\ODBC.INI
If a DSN does not appear in the ODBC Administrator (odbcad32.exe) it might be because the DSN name is not included in the list of DSNs in the corresponding subkey
...\ODBC.INI\ODBC Data Sources
Paths to odbcad32.exe:
x86:
%windir%\syswow64\odbcad32.exe
x64:
%windir%\system32\odbcad32.exe

Answer 2

I was able to find the "Machine Data Sources" that Microsoft Access creates in the Windows Registry Here:
Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\ClickToRun\REGISTRY\MACHINE\Software\ODBC\ODBC.INI\ODBC
Data Sources
The "Machine Data Sources" that are in this part of the registry, seem to be accessible only via MS Access. If you look for them instead using the standard Windows ODBC Data Source Administrator "widgets" (32 or 64 bit), you just don't see the "Access Created" Machine Data Sources for some reason. If anyone can tell us why, that would be great!
What's more frustrating, is that at least with the latest Microsoft Access Office 365 version, you can only create NEW Machine Data Sources. You can't delete or edit existing "Machine Data Sources".
That being said, if you avoid creating the "Machine Data Sources" using Microsoft Access itself, and instead use the standard 64 Bit Windows ODBC Data Source Administrator "widget", then for whatever reason Access will see those that you create in this way.
So having the issue that you're describing, just seems to be the result of some weird design that Microsoft has implemented specifically in regard to Microsoft Access ODBC connections, for a reason that escapes me.
Hope this helps!

Answer 3

Below is an alternative to accessing the Windows Registry:
Control Panel
Administrative Tools
ODBC Data Sources (32-bit or 64-bit)
Click the tab for: User DSN, System DSN, or File DSN
Click the name of the Data Source
Click Configure... if you would like to view or modify the details of the data source