diff --git a/filestore.go b/filestore.go
index 2a548cadb..e0766fd08 100644
--- a/filestore.go
+++ b/filestore.go
@@ -61,10 +61,18 @@ func NewFileStoreFactory(settings *Settings) MessageStoreFactory {
 
 // Create creates a new FileStore implementation of the MessageStore interface.
 func (f fileStoreFactory) Create(sessionID SessionID) (msgStore MessageStore, err error) {
+	globalSettings := f.settings.GlobalSettings()
+	dynamicSessions, _ := globalSettings.BoolSetting(config.DynamicSessions)
+
 	sessionSettings, ok := f.settings.SessionSettings()[sessionID]
 	if !ok {
-		return nil, fmt.Errorf("unknown session: %v", sessionID)
+		if dynamicSessions {
+			sessionSettings = globalSettings
+		} else {
+			return nil, fmt.Errorf("unknown session: %v", sessionID)
+		}
 	}
+
 	dirname, err := sessionSettings.Setting(config.FileStorePath)
 	if err != nil {
 		return nil, err
diff --git a/mongostore.go b/mongostore.go
index c9bc37ac2..290cdc236 100644
--- a/mongostore.go
+++ b/mongostore.go
@@ -61,9 +61,16 @@ func NewMongoStoreFactoryPrefixed(settings *Settings, collectionsPrefix string)
 
 // Create creates a new MongoStore implementation of the MessageStore interface.
 func (f mongoStoreFactory) Create(sessionID SessionID) (msgStore MessageStore, err error) {
+	globalSettings := f.settings.GlobalSettings()
+	dynamicSessions, _ := globalSettings.BoolSetting(config.DynamicSessions)
+
 	sessionSettings, ok := f.settings.SessionSettings()[sessionID]
 	if !ok {
-		return nil, fmt.Errorf("unknown session: %v", sessionID)
+		if dynamicSessions {
+			sessionSettings = globalSettings
+		} else {
+			return nil, fmt.Errorf("unknown session: %v", sessionID)
+		}
 	}
 	mongoConnectionURL, err := sessionSettings.Setting(config.MongoStoreConnection)
 	if err != nil {
diff --git a/sqlstore.go b/sqlstore.go
index 6ff8ac225..5e492be2c 100644
--- a/sqlstore.go
+++ b/sqlstore.go
@@ -67,10 +67,18 @@ func NewSQLStoreFactory(settings *Settings) MessageStoreFactory {
 
 // Create creates a new SQLStore implementation of the MessageStore interface.
 func (f sqlStoreFactory) Create(sessionID SessionID) (msgStore MessageStore, err error) {
+	globalSettings := f.settings.GlobalSettings()
+	dynamicSessions, _ := globalSettings.BoolSetting(config.DynamicSessions)
+
 	sessionSettings, ok := f.settings.SessionSettings()[sessionID]
 	if !ok {
-		return nil, fmt.Errorf("unknown session: %v", sessionID)
+		if dynamicSessions {
+			sessionSettings = globalSettings
+		} else {
+			return nil, fmt.Errorf("unknown session: %v", sessionID)
+		}
 	}
+
 	sqlDriver, err := sessionSettings.Setting(config.SQLStoreDriver)
 	if err != nil {
 		return nil, err