diff --git a/server/channelserver/handlers_data.go b/server/channelserver/handlers_data.go
index 3a2264ce1..17f11ccca 100644
--- a/server/channelserver/handlers_data.go
+++ b/server/channelserver/handlers_data.go
@@ -25,6 +25,11 @@ func handleMsgMhfSavedata(s *Session, p mhfpacket.MHFPacket) {
 		doAckSimpleFail(s, pkt.AckHandle, make([]byte, 4))
 		return
 	}
+	// Snapshot current house tier before applying the update so we can
+	// restore it if the incoming data is corrupted (issue #92).
+	prevHouseTier := make([]byte, len(characterSaveData.HouseTier))
+	copy(prevHouseTier, characterSaveData.HouseTier)
+
 	// Var to hold the decompressed savedata for updating the launcher response fields.
 	if pkt.SaveType == 1 {
 		// Diff-based update.
@@ -55,6 +60,20 @@ func handleMsgMhfSavedata(s *Session, p mhfpacket.MHFPacket) {
 	}
 	characterSaveData.updateStructWithSaveData()
 
+	// Mitigate house theme corruption (issue #92): the game client
+	// sometimes sends house_tier as -1 (all 0xFF bytes), which causes
+	// the house theme to vanish on next login. If the new value looks
+	// corrupted, restore the previous value in both the struct and the
+	// decompressed blob so Save() persists consistent data.
+	if len(prevHouseTier) > 0 && characterSaveData.isHouseTierCorrupted() {
+		s.logger.Warn("Detected corrupted house_tier in save data, restoring previous value",
+			zap.Binary("corrupted", characterSaveData.HouseTier),
+			zap.Binary("restored", prevHouseTier),
+			zap.Uint32("charID", s.charID),
+		)
+		characterSaveData.restoreHouseTier(prevHouseTier)
+	}
+
 	s.playtime = characterSaveData.Playtime
 	s.playtimeTime = time.Now()
 
diff --git a/server/channelserver/model_character.go b/server/channelserver/model_character.go
index f732b1042..055d728bd 100644
--- a/server/channelserver/model_character.go
+++ b/server/channelserver/model_character.go
@@ -202,3 +202,27 @@ func (save *CharacterSaveData) updateStructWithSaveData() {
 		}
 	}
 }
+
+// isHouseTierCorrupted checks whether the house tier field contains 0xFF
+// bytes, which indicates an uninitialized or -1 value from the game client.
+// The game uses small positive integers for theme IDs; 0xFF is never valid.
+func (save *CharacterSaveData) isHouseTierCorrupted() bool {
+	for _, b := range save.HouseTier {
+		if b == 0xFF {
+			return true
+		}
+	}
+	return false
+}
+
+// restoreHouseTier replaces the current house tier with the given value in
+// both the struct field and the underlying decompressed save blob, keeping
+// them consistent for Save().
+func (save *CharacterSaveData) restoreHouseTier(valid []byte) {
+	save.HouseTier = make([]byte, len(valid))
+	copy(save.HouseTier, valid)
+	offset, ok := save.Pointers[pHouseTier]
+	if ok && offset+len(valid) <= len(save.decompSave) {
+		copy(save.decompSave[offset:offset+len(valid)], valid)
+	}
+}