diff --git a/app/dns/server.go b/app/dns/server.go
index 5fbec9b91..dbe879baf 100644
--- a/app/dns/server.go
+++ b/app/dns/server.go
@@ -105,6 +105,10 @@ func (s *Server) cleanup() {
 			delete(s.records, d)
 		}
 	}
+
+	if len(s.records) == 0 {
+		s.records = make(map[string]*DomainRecord)
+	}
 }
 
 func (s *Server) LookupIP(domain string) ([]net.IP, error) {
diff --git a/app/proxyman/mux/session.go b/app/proxyman/mux/session.go
index c828d21c8..d42814c97 100644
--- a/app/proxyman/mux/session.go
+++ b/app/proxyman/mux/session.go
@@ -73,6 +73,10 @@ func (m *SessionManager) Remove(id uint16) {
 	}
 
 	delete(m.sessions, id)
+
+	if len(m.sessions) == 0 {
+		m.sessions = make(map[uint16]*Session, 16)
+	}
 }
 
 func (m *SessionManager) Get(id uint16) (*Session, bool) {
diff --git a/proxy/vmess/encoding/server.go b/proxy/vmess/encoding/server.go
index d3f713c34..19ea32eb6 100644
--- a/proxy/vmess/encoding/server.go
+++ b/proxy/vmess/encoding/server.go
@@ -78,6 +78,10 @@ func (h *SessionHistory) removeExpiredEntries() {
 			delete(h.cache, session)
 		}
 	}
+
+	if len(h.cache) == 0 {
+		h.cache = make(map[sessionId]time.Time, 128)
+	}
 }
 
 type ServerSession struct {