Sudden Microsoft Access reporting: “make sure this is a valid datasource”

Symptom

As of September 2020 some customers are reporting, from a project that used to work smoothly:

Opening table ....
from data source "DRIVER={Microsoft Access Driver (*.mdb, *.accdb ....
make sure this is a valid datasource.

Diagnose

Using the ODBC data sources (64 bit) app, try to create a system dsn to the Microsoft Access database file. When the error message:

The setup routines for the Microsoft Access Driver (*.mdb, *.accdb) ODBC driver could not be loaded due to system error code 1114:
A dynamic link library (DLL) initialization routine failed.
(C:\Program Files\Microsoft Office\root\VFS\ProgramFilesCommonX64\Microsoft Shared\Office16\ACEODBC.DLL).

appears, this indicates an installation error.

Fix

The following tip from stackoverflow may help:

Settings -> Add/Remove Programs-> Select “Microsoft Access database engine” and select Modify.