As system (and user) DSN information is stored in the Windows registry, you are basically asking whether changes in the registry are tracked/logged.

AFAIK the registry can itself use auditing (disabled by default), and there is the API RegNotifyChangeKeyValue that allows programs to be notified about registry changes.

Additionally, tools like Sysinternals's Process Monitor can be used to track changes but I guess not post mortem...

So generally, you may search for answers in general Windows forums...

Two things to have the client check:

1) Are they using the correct ODBC tool (32-bit or 64-bit) to look for the DSN? Windows has a separate tool for each. You might have to explain which one your application uses.

2) Are they checking for both System DSNs and User DSNs? The DSN might have been installed in either place, depending on how the install happened.

The creation and deletion of SQL Anywhere DSNs can be automated by running the dbdsn.exe utility with the -ws, -wu and -d options (create as System, create as User, and delete).

I am not familiar with the Micros setup, but most embedded products use all the automation they can to hide the setup from view.

Perhaps something went awry with maintenance or customization of the setup.

FWIW applications can free themselves from dependence on DSNs by using a DSN-less connection string. In many cases, this can be as simple as coding this as the connection string

ENG=ddd; DBN=ddd; UID=dba; PWD=sql; DRIVER=SQL Anywhere 11;

instead of DSN=whatever.

Thank you all for the information and advice for the above question. We will certainly check with customer and explain which ODBC (Micros uses 32 Bit) to check. Thanks again.