I've been working on a small TKinter application to sort tabular data from feature classes. To make it user friendly, first the user would select a database from a standard file browser. Then the application walks the database using arcpy.da.Walk, and creates a dropdown menu containing the feature classes.
This application was developed for arcGIS 10.3 and worked as it should. Now my organisation has upgraded to ArcGIS 10.5.1 and for reasons beyond my understanding the walk function doesn't return anything when the workspace is set to an .mdb file.
I've tried running the walk function in other environments, but get the same result. The same problem seems to exist for the ListFeatureClasses function, who doesn't return anything.