diff --git a/src/servers/sapphire_zone/Zone/InstanceContent.h b/src/servers/sapphire_zone/Zone/InstanceContent.h
index a4d0e4be..d55fcd82 100644
--- a/src/servers/sapphire_zone/Zone/InstanceContent.h
+++ b/src/servers/sapphire_zone/Zone/InstanceContent.h
@@ -85,7 +85,7 @@ private:
    uint16_t m_currentBgm;
 
    int64_t m_instanceExpireTime;
-   int64_t m_instanceCommenceTime;
+   uint64_t m_instanceCommenceTime;
 
    Entity::EventObjectPtr m_pEntranceEObj;