We were asked to discover why a vital computer to computer link was prone to fail at embarrassing moments; bringing down the communication between employees clocking in and out and the third party payroll bureau. We discovered a hotch-potch of components written by long departed outside contractors, designed for Unix but co-erced into a Windows environment under emulation, presumably because the original developer could not find a Windows implementation of the required protocol.
We located the original protocol, now open-sourced, and implemented it in a Windows service. We achieved drastic simplification, greatly enhanced reliability and much simpler operation as well as providing the client with all the source code to safeguard it for the future.