diff --git a/.gitignore b/.gitignore
index 42069af..4df8e63 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,4 @@
 __debug_bin.exe
 *.log
 config.json
+tavern.exe
diff --git a/core/group_instant.go b/core/group_instant.go
index 40dc77d..2015053 100644
--- a/core/group_instant.go
+++ b/core/group_instant.go
@@ -111,6 +111,9 @@ func (gd *instantDoc) removeMember(mid accountID) error {
 
 func (gd *instantDoc) getMembers() (map[primitive.ObjectID]any, error) {
 	res, err := gd.rh.JSONGet(gd.strid(), "$._members")
+	if err == redis.Nil {
+		return nil, nil
+	}
 	if err != nil {
 		return nil, err
 	}
@@ -250,20 +253,20 @@ func (gi *groupInstant) Join(w http.ResponseWriter, r *http.Request) {
 	}
 
 	if data.Gid.IsZero() || data.Mid.IsZero() {
-		logger.Error("groupInstant.Join failed. gid or mid is zero")
+		logger.Println("groupInstant.Join failed. gid or mid is zero")
 		w.WriteHeader(http.StatusBadRequest)
 		return
 	}
 
 	gd, err := gi.find(data.Gid)
 	if err != nil || gd == nil {
-		logger.Error("groupInstant.Join failed. gi find return err :", err)
+		logger.Println("groupInstant.Join failed. gi find return err :", err)
 		w.WriteHeader(http.StatusInternalServerError)
 		return
 	}
 
 	if err := gi.join(gd, data.Mid, data.Character); err != nil {
-		logger.Error("groupInstant.Join failed :", err)
+		logger.Println("groupInstant.Join failed :", err)
 		w.WriteHeader(http.StatusInternalServerError)
 	} else {
 		gocommon.MakeEncoder(w, r).Encode(gd.Count)
@@ -377,12 +380,21 @@ func (gi *groupInstant) Merge(w http.ResponseWriter, r *http.Request) {
 	}
 	// From에 있는 mid를 Into로 옮김
 	gdinto, err := gi.find(data.Into)
-	if err != nil || gdinto == nil {
+	if err != nil {
 		logger.Println("groupInstant.Merge failed. gd.getMembers returns err :", err)
 		w.WriteHeader(http.StatusInternalServerError)
 		return
 	}
 
+	if gdinto == nil {
+		// 이미 나갔다. 머지 중단
+		gocommon.MakeEncoder(w, r).Encode(struct {
+			From int64
+			Into int64
+		}{From: -1, Into: 0}) // -1: 알수 없음, 0: 비었음
+		return
+	}
+
 	gdfrom := instantDoc{
 		Gid: data.From,
 		rh:  gi.rh,
@@ -394,6 +406,15 @@ func (gi *groupInstant) Merge(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	if len(fromMembers) == 0 {
+		// gdfrom이 비었다. 머지 중단
+		gocommon.MakeEncoder(w, r).Encode(struct {
+			From int64
+			Into int64
+		}{From: 0, Into: -1})
+		return
+	}
+
 	var movedmids []primitive.ObjectID
 	for mid, doc := range fromMembers {
 		gi.join(gdinto, mid, doc)
diff --git a/core/group_party.go b/core/group_party.go
index efbea50..99d0120 100644
--- a/core/group_party.go
+++ b/core/group_party.go
@@ -314,8 +314,8 @@ func (gp *groupParty) JoinParty(w http.ResponseWriter, r *http.Request) {
 		// 이미 멤버여야 재입장 가능
 		path := "$._members." + gd.tid(mid) + "._body"
 		if _, err := gd.rh.JSONSet(gd.strid(), path, character, gocommon.RedisonSetOptionXX); err != nil {
-			// 멤버가 아니네?
-			logger.Error("JoinParty failed :", err)
+			// 멤버가 아니네? 그새 파티장이 쫓아냈나보다
+			logger.Println("JoinParty failed. maybe kicked by party owner :", err)
 			w.WriteHeader(http.StatusInternalServerError)
 			return
 		}
@@ -324,7 +324,7 @@ func (gp *groupParty) JoinParty(w http.ResponseWriter, r *http.Request) {
 	gp.rh.JSONSet(mid.Hex(), "$.party", bson.M{"id": gid.Hex()})
 	memdoc, err := gd.addMember(mid, character)
 	if err != nil {
-		logger.Error("JoinParty failed :", err)
+		logger.Println("JoinParty failed :", err)
 		w.WriteHeader(http.StatusInternalServerError)
 		return
 	}
@@ -363,7 +363,7 @@ func (gp *groupParty) ConditionalClearPartyMember(w http.ResponseWriter, r *http
 
 	pids, err := gp.rh.JSONGetString(doc.Mid, "$.party.id")
 	if err != nil {
-		logger.Error("ConditionalClearPartyMember failed. gp.rh.JSONGetString returns err :", err)
+		logger.Println("ConditionalClearPartyMember failed. gp.rh.JSONGetString returns err :", err)
 		w.WriteHeader(http.StatusInternalServerError)
 		return
 	}
@@ -519,7 +519,7 @@ func (gp *groupParty) AcceptPartyInvitation(w http.ResponseWriter, r *http.Reque
 
 	cnt, err := gp.rh.Del(context.Background(), "inv."+mid.Hex()).Result()
 	if err != nil {
-		logger.Error("AcceptPartyInvitation failed. gp.rh.Del returns err :", err)
+		logger.Println("AcceptPartyInvitation failed. gp.rh.Del returns err :", err)
 		w.WriteHeader(http.StatusInternalServerError)
 		return
 	}
@@ -532,7 +532,7 @@ func (gp *groupParty) AcceptPartyInvitation(w http.ResponseWriter, r *http.Reque
 
 	pids, err := gp.rh.JSONGetString(mid.Hex(), "$.party.id")
 	if err != nil {
-		logger.Error("AcceptPartyInvitation failed. gp.rh.JSONGetString returns err :", err)
+		logger.Println("AcceptPartyInvitation failed. gp.rh.JSONGetString returns err :", err)
 		w.WriteHeader(http.StatusInternalServerError)
 		return
 	}
@@ -669,7 +669,7 @@ func (gp *groupParty) UpdatePartyDocument(w http.ResponseWriter, r *http.Request
 	frag := data.Doc
 
 	if err := gp.updatePartyDocument(gid, frag); err != nil {
-		logger.Error("UpdatePartyDocument failed. group.UpdatePartyDocument returns err :", err)
+		logger.Println("UpdatePartyDocument failed. group.UpdatePartyDocument returns err :", err)
 		w.WriteHeader(http.StatusBadRequest)
 		return
 	}
@@ -690,13 +690,13 @@ func (gp *groupParty) QueryPartyMembers(w http.ResponseWriter, r *http.Request)
 
 	members, err := gd.getMembers()
 	if err != nil {
-		logger.Error("QueryPartyMembers failed. group.QueryPartyMembers returns err :", err)
+		logger.Println("QueryPartyMembers failed. group.QueryPartyMembers returns err :", err)
 		w.WriteHeader(http.StatusBadRequest)
 		return
 	}
 
 	if err := gocommon.MakeEncoder(w, r).Encode(members); err != nil {
-		logger.Error("QueryPartyMembers failed. writeBsonDoc return err :", err)
+		logger.Println("QueryPartyMembers failed. writeBsonDoc return err :", err)
 		w.WriteHeader(http.StatusInternalServerError)
 		return
 	}