Sdb Sdb files are Shim Databases. They contain information about bad applications, and about the fixes that can be applied to them. Shims A shim is a piece of code that influences the process it's applied to. This can be done by calling certain api's, or by changing the behavior of api's. 'DisableThemes' is an example of a shim that changes behavior by calling 'SetThemeAppProperties'. 'Win95VersionLie' is an example of a shim that changes behavior, by intercepting calls to GetVersion[Ex]. Layers A layer is a collection (1..n) of shims. Layers are used to reference a collection of shims by name.