A system and method for configuring authentication of a mobile communications device entail detecting user context and device context factors and determining whether a current authentication mode is impractical or unfeasible in view of such factors. User context information of interest includes any indication that the user is driving or in a meeting for example. Context factors of interest include for example such factors as light, noise, or user activities such as driving. Based on this user context and device context, if the currently set authentication mode is impractical or unfeasible, then the device may select an available alternative authentication mode and reconfigure the device for that mode.