We recently inherited a very complex and powerful Microsoft Access application that a company has been working on over the past 10+ years. Their developer had moved on and they decided to outsource the ongoing support and development. The application is used by around 30 users and uses both Access and SQL Server as a back-end.
It’s in scenarios like this that I often use a tool such as the Analyzer for Microsoft Access.
It documents SQL Server (and other linked databases) and Access databases and will create a list of table names, data dictionary, relationships, indexes and general statistics about the data. It also reads what is defined for forms and reports — names, sources, controls, groups, sections, conditional formatting, and much more. This is a terrific tool for a new developer getting up to speed on a system.