diff --git a/app/app.go b/app/app.go
index 69811eb..37114b2 100644
--- a/app/app.go
+++ b/app/app.go
@@ -146,6 +146,7 @@ func NewApp(cfg *Config) (*App, error) {
 // Run imports the library and starts server.
 func (a *App) Run() error {
 	for _, pc := range a.Config.Library {
+		pc.Path = filepath.Clean(pc.Path)
 		p := &media.Path{
 			Path:   pc.Path,
 			Prefix: pc.Prefix,
diff --git a/media/library.go b/media/library.go
index 7de68e0..0657847 100644
--- a/media/library.go
+++ b/media/library.go
@@ -35,10 +35,10 @@ func (lib *Library) AddPath(p *Path) error {
 	// make sure new path doesn't collide with existing ones
 	for _, p2 := range lib.Paths {
 		if p.Path == p2.Path {
-			return errors.New("media: duplicate library path")
+			return errors.New(fmt.Sprintf("media: duplicate (normalized) library path '%s'", p.Path))
 		}
 		if p.Prefix == p2.Prefix {
-			return errors.New("media: duplicate library prefix")
+			return errors.New(fmt.Sprintf("media: duplicate library prefix '%s'", p.Prefix))
 		}
 	}
 	if err := os.MkdirAll(p.Path, 0755); err != nil {