As stated in the MSDN article that all Keys under HKLM\Software are virtualized, there is still the HKLM\Software\ODBC\ODBC.INI key (For creating System DSNs) that will NOT be virtualized.
The rationale behind this was that – Creating a System DSN would essentially be a task of an Administrator and so when you write to this location as a Standard User you will get an exception as the Registry entry is marked for no virtualization
To view these settings, in the Command prompt type in
REG FLAGS HKLM\Software\ODBC\ODBC.INI
And this will output ->