diff --git a/server/channelserver/handlers_festa.go b/server/channelserver/handlers_festa.go
index 12ac0b86c..851eebb42 100644
--- a/server/channelserver/handlers_festa.go
+++ b/server/channelserver/handlers_festa.go
@@ -338,7 +338,11 @@ func handleMsgMhfStateFestaU(s *Session, p mhfpacket.MHFPacket) {
 	guild, err := s.server.guildRepo.GetByCharID(s.charID)
 	applicant := false
 	if guild != nil {
-		applicant, _ = s.server.guildRepo.HasApplication(guild.ID, s.charID)
+		var appErr error
+		applicant, appErr = s.server.guildRepo.HasApplication(guild.ID, s.charID)
+		if appErr != nil {
+			s.logger.Warn("Failed to check guild application status", zap.Error(appErr))
+		}
 	}
 	if err != nil || guild == nil || applicant {
 		doAckSimpleFail(s, pkt.AckHandle, make([]byte, 4))
@@ -367,7 +371,11 @@ func handleMsgMhfStateFestaG(s *Session, p mhfpacket.MHFPacket) {
 	guild, err := s.server.guildRepo.GetByCharID(s.charID)
 	applicant := false
 	if guild != nil {
-		applicant, _ = s.server.guildRepo.HasApplication(guild.ID, s.charID)
+		var appErr error
+		applicant, appErr = s.server.guildRepo.HasApplication(guild.ID, s.charID)
+		if appErr != nil {
+			s.logger.Warn("Failed to check guild application status", zap.Error(appErr))
+		}
 	}
 	resp := byteframe.NewByteFrame()
 	if err != nil || guild == nil || applicant {
diff --git a/server/channelserver/handlers_guild_board.go b/server/channelserver/handlers_guild_board.go
index 8ca6fecc8..e14ce53e5 100644
--- a/server/channelserver/handlers_guild_board.go
+++ b/server/channelserver/handlers_guild_board.go
@@ -59,7 +59,11 @@ func handleMsgMhfUpdateGuildMessageBoard(s *Session, p mhfpacket.MHFPacket) {
 	guild, err := s.server.guildRepo.GetByCharID(s.charID)
 	applicant := false
 	if guild != nil {
-		applicant, _ = s.server.guildRepo.HasApplication(guild.ID, s.charID)
+		var appErr error
+		applicant, appErr = s.server.guildRepo.HasApplication(guild.ID, s.charID)
+		if appErr != nil {
+			s.logger.Warn("Failed to check guild application status", zap.Error(appErr))
+		}
 	}
 	if err != nil || guild == nil || applicant {
 		doAckSimpleSucceed(s, pkt.AckHandle, make([]byte, 4))
diff --git a/server/channelserver/handlers_guild_ops.go b/server/channelserver/handlers_guild_ops.go
index 5cc30e594..0e1debafd 100644
--- a/server/channelserver/handlers_guild_ops.go
+++ b/server/channelserver/handlers_guild_ops.go
@@ -51,13 +51,19 @@ func handleMsgMhfOperateGuild(s *Session, p mhfpacket.MHFPacket) {
 					guild.LeaderCharID = guildMembers[i].CharID
 					guildMembers[0].OrderIndex = guildMembers[i].OrderIndex
 					guildMembers[i].OrderIndex = 1
-					_ = s.server.guildRepo.SaveMember(guildMembers[0])
-					_ = s.server.guildRepo.SaveMember(guildMembers[i])
+					if err := s.server.guildRepo.SaveMember(guildMembers[0]); err != nil {
+						s.logger.Error("Failed to save former leader member data", zap.Error(err))
+					}
+					if err := s.server.guildRepo.SaveMember(guildMembers[i]); err != nil {
+						s.logger.Error("Failed to save new leader member data", zap.Error(err))
+					}
 					bf.WriteUint32(guildMembers[i].CharID)
 					break
 				}
 			}
-			_ = s.server.guildRepo.Save(guild)
+			if err := s.server.guildRepo.Save(guild); err != nil {
+				s.logger.Error("Failed to save guild after leadership resign", zap.Error(err))
+			}
 		}
 	case mhfpacket.OperateGuildApply:
 		err = s.server.guildRepo.CreateApplication(guild.ID, s.charID, s.charID, GuildApplicationTypeApplied)
@@ -76,9 +82,11 @@ func handleMsgMhfOperateGuild(s *Session, p mhfpacket.MHFPacket) {
 		if err != nil {
 			response = 0
 		} else {
-			_ = s.server.mailRepo.SendMail(0, s.charID, "Withdrawal",
+			if err := s.server.mailRepo.SendMail(0, s.charID, "Withdrawal",
 				fmt.Sprintf("You have withdrawn from 「%s」.", guild.Name),
-				0, 0, false, true)
+				0, 0, false, true); err != nil {
+				s.logger.Warn("Failed to send guild withdrawal notification", zap.Error(err))
+			}
 		}
 		bf.WriteUint32(uint32(response))
 	case mhfpacket.OperateGuildDonateRank:
@@ -101,7 +109,9 @@ func handleMsgMhfOperateGuild(s *Session, p mhfpacket.MHFPacket) {
 			return
 		}
 		guild.Comment, _ = stringsupport.SJISToUTF8(pkt.Data2.ReadNullTerminatedBytes())
-		_ = s.server.guildRepo.Save(guild)
+		if err := s.server.guildRepo.Save(guild); err != nil {
+			s.logger.Error("Failed to save guild comment", zap.Error(err))
+		}
 	case mhfpacket.OperateGuildUpdateMotto:
 		if !characterGuildInfo.IsLeader && !characterGuildInfo.IsSubLeader() {
 			doAckSimpleFail(s, pkt.AckHandle, make([]byte, 4))
@@ -110,7 +120,9 @@ func handleMsgMhfOperateGuild(s *Session, p mhfpacket.MHFPacket) {
 		_ = pkt.Data1.ReadUint16()
 		guild.SubMotto = pkt.Data1.ReadUint8()
 		guild.MainMotto = pkt.Data1.ReadUint8()
-		_ = s.server.guildRepo.Save(guild)
+		if err := s.server.guildRepo.Save(guild); err != nil {
+			s.logger.Error("Failed to save guild motto", zap.Error(err))
+		}
 	case mhfpacket.OperateGuildRenamePugi1:
 		handleRenamePugi(s, pkt.Data2, guild, 1)
 	case mhfpacket.OperateGuildRenamePugi2:
@@ -165,7 +177,9 @@ func handleRenamePugi(s *Session, bf *byteframe.ByteFrame, guild *Guild, num int
 	default:
 		guild.PugiName3 = name
 	}
-	_ = s.server.guildRepo.Save(guild)
+	if err := s.server.guildRepo.Save(guild); err != nil {
+		s.logger.Error("Failed to save guild pugi name", zap.Error(err))
+	}
 }
 
 func handleChangePugi(s *Session, outfit uint8, guild *Guild, num int) {
@@ -177,7 +191,9 @@ func handleChangePugi(s *Session, outfit uint8, guild *Guild, num int) {
 	case 3:
 		guild.PugiOutfit3 = outfit
 	}
-	_ = s.server.guildRepo.Save(guild)
+	if err := s.server.guildRepo.Save(guild); err != nil {
+		s.logger.Error("Failed to save guild pugi outfit", zap.Error(err))
+	}
 }
 
 func handleDonateRP(s *Session, amount uint16, guild *Guild, _type int) []byte {
@@ -299,7 +315,9 @@ func handleMsgMhfOperateGuildMember(s *Session, p mhfpacket.MHFPacket) {
 	if err != nil {
 		doAckSimpleFail(s, pkt.AckHandle, make([]byte, 4))
 	} else {
-		_ = s.server.mailRepo.SendMail(mail.SenderID, mail.RecipientID, mail.Subject, mail.Body, 0, 0, false, true)
+		if err := s.server.mailRepo.SendMail(mail.SenderID, mail.RecipientID, mail.Subject, mail.Body, 0, 0, false, true); err != nil {
+			s.logger.Warn("Failed to send guild member operation mail", zap.Error(err))
+		}
 		if s.server.Registry != nil {
 			s.server.Registry.NotifyMailToCharID(pkt.CharID, s, &mail)
 		} else {
diff --git a/server/channelserver/handlers_guild_scout.go b/server/channelserver/handlers_guild_scout.go
index b0bb1a0b6..292878483 100644
--- a/server/channelserver/handlers_guild_scout.go
+++ b/server/channelserver/handlers_guild_scout.go
@@ -148,7 +148,9 @@ func handleMsgMhfAnswerGuildScout(s *Session, p mhfpacket.MHFPacket) {
 		bf.WriteUint32(guild.ID)
 		doAckBufSucceed(s, pkt.AckHandle, bf.Data())
 		for _, m := range msgs {
-			_ = s.server.mailRepo.SendMail(m.senderID, m.recipientID, m.subject, m.body, 0, 0, false, true)
+			if err := s.server.mailRepo.SendMail(m.senderID, m.recipientID, m.subject, m.body, 0, 0, false, true); err != nil {
+				s.logger.Warn("Failed to send guild scout response mail", zap.Error(err))
+			}
 		}
 	}
 }
diff --git a/server/channelserver/handlers_house.go b/server/channelserver/handlers_house.go
index 9185c3905..35298335d 100644
--- a/server/channelserver/handlers_house.go
+++ b/server/channelserver/handlers_house.go
@@ -402,12 +402,14 @@ func addWarehouseItem(s *Session, item mhfitem.MHFItemStack) {
 
 func warehouseGetItems(s *Session, index uint8) []mhfitem.MHFItemStack {
 	initializeWarehouse(s)
-	var data []byte
 	var items []mhfitem.MHFItemStack
 	if index > 10 {
 		return items
 	}
-	data, _ = s.server.houseRepo.GetWarehouseItemData(s.charID, index)
+	data, err := s.server.houseRepo.GetWarehouseItemData(s.charID, index)
+	if err != nil {
+		s.logger.Warn("Failed to load warehouse item data", zap.Error(err))
+	}
 	if len(data) > 0 {
 		box := byteframe.NewByteFrameFromBytes(data)
 		numStacks := box.ReadUint16()
@@ -420,12 +422,14 @@ func warehouseGetItems(s *Session, index uint8) []mhfitem.MHFItemStack {
 }
 
 func warehouseGetEquipment(s *Session, index uint8) []mhfitem.MHFEquipment {
-	var data []byte
 	var equipment []mhfitem.MHFEquipment
 	if index > 10 {
 		return equipment
 	}
-	data, _ = s.server.houseRepo.GetWarehouseEquipData(s.charID, index)
+	data, err := s.server.houseRepo.GetWarehouseEquipData(s.charID, index)
+	if err != nil {
+		s.logger.Warn("Failed to load warehouse equipment data", zap.Error(err))
+	}
 	if len(data) > 0 {
 		box := byteframe.NewByteFrameFromBytes(data)
 		numStacks := box.ReadUint16()
diff --git a/server/channelserver/handlers_items.go b/server/channelserver/handlers_items.go
index 7444b4ebc..63ac17eb1 100644
--- a/server/channelserver/handlers_items.go
+++ b/server/channelserver/handlers_items.go
@@ -188,9 +188,11 @@ func handleMsgMhfEnumerateOrder(s *Session, p mhfpacket.MHFPacket) {
 func handleMsgMhfGetExtraInfo(s *Session, p mhfpacket.MHFPacket) {}
 
 func userGetItems(s *Session) []mhfitem.MHFItemStack {
-	var data []byte
 	var items []mhfitem.MHFItemStack
-	data, _ = s.server.userRepo.GetItemBox(s.userID)
+	data, err := s.server.userRepo.GetItemBox(s.userID)
+	if err != nil {
+		s.logger.Warn("Failed to load user item box", zap.Error(err))
+	}
 	if len(data) > 0 {
 		box := byteframe.NewByteFrameFromBytes(data)
 		numStacks := box.ReadUint16()
@@ -247,7 +249,10 @@ func handleMsgMhfCheckWeeklyStamp(s *Session, p mhfpacket.MHFPacket) {
 		updated = 1
 	}
 
-	total, redeemed, _ = s.server.stampRepo.GetTotals(s.charID, pkt.StampType)
+	total, redeemed, err = s.server.stampRepo.GetTotals(s.charID, pkt.StampType)
+	if err != nil {
+		s.logger.Warn("Failed to get stamp totals", zap.Error(err))
+	}
 	bf := byteframe.NewByteFrame()
 	bf.WriteUint16(total)
 	bf.WriteUint16(redeemed)
diff --git a/server/channelserver/handlers_mercenary.go b/server/channelserver/handlers_mercenary.go
index 93419a92c..9dfdec8ab 100644
--- a/server/channelserver/handlers_mercenary.go
+++ b/server/channelserver/handlers_mercenary.go
@@ -212,7 +212,11 @@ func handleMsgMhfReadMercenaryW(s *Session, p mhfpacket.MHFPacket) {
 	var cid uint32
 	var name string
 	if pactID > 0 {
-		cid, name, _ = s.server.charRepo.FindByRastaID(pactID)
+		var findErr error
+		cid, name, findErr = s.server.charRepo.FindByRastaID(pactID)
+		if findErr != nil {
+			s.logger.Warn("Failed to find character by rasta ID", zap.Error(findErr))
+		}
 		bf.WriteUint8(1) // numLends
 		bf.WriteUint32(uint32(pactID))
 		bf.WriteUint32(cid)
diff --git a/server/channelserver/handlers_rengoku.go b/server/channelserver/handlers_rengoku.go
index 2571c114d..f02df0bab 100644
--- a/server/channelserver/handlers_rengoku.go
+++ b/server/channelserver/handlers_rengoku.go
@@ -202,7 +202,11 @@ func handleMsgMhfEnumerateRengokuRanking(s *Session, p mhfpacket.MHFPacket) {
 	guild, _ := s.server.guildRepo.GetByCharID(s.charID)
 	var isApplicant bool
 	if guild != nil {
-		isApplicant, _ = s.server.guildRepo.HasApplication(guild.ID, s.charID)
+		var appErr error
+		isApplicant, appErr = s.server.guildRepo.HasApplication(guild.ID, s.charID)
+		if appErr != nil {
+			s.logger.Warn("Failed to check guild application status", zap.Error(appErr))
+		}
 	}
 	if isApplicant {
 		guild = nil