When you get around to installing vSphere, if on a 64-bit Windows host in x86 compatibility mode, a 32-bit DSN is required for the database connection.
If a DSN has been set up through Start > Administrative Tools > Data Sources (ODBC) the vSphere installer won’t be able to use this DSN.
The 64-bit ODBC Administrator tool can be invoked from Control Panel to manage user DSNs and system DSNs that are used by 64-bit processes, but for 32-bit data sources, the 32-bit ODBC Administrator tool is used for Windows on Windows 64 (WOW64) processes.
To set up a 32-bit DSN launch the 32-bit version of the Data Source Administrator
It is located at:
The vSphere installer will then be able to detect the DSN and continue the installation.
Please see the Microsoft KB article https://support.microsoft.com/default.aspx/kb/942976/en-us for more information.
If you get the error: DSN is pointing to an unsupported ODBC driver then see KB article: https://kb.vmware.com/kb/1015804