diff --git a/studio-v2/app/messages/_components/ChatArea.tsx b/studio-v2/app/messages/_components/ChatArea.tsx
index f66b39b..ddb8f0b 100644
--- a/studio-v2/app/messages/_components/ChatArea.tsx
+++ b/studio-v2/app/messages/_components/ChatArea.tsx
@@ -188,7 +188,7 @@ function ChatHeader({ isDark, conversation, contact, showContactInfo, setShowCon
               <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={1.5} d="M5 5a2 2 0 012-2h10a2 2 0 012 2v16l-7-3.5L5 21V5z" />
             </svg>
           </HeaderButton>
-          <HeaderButton isDark={isDark} active={conversation.muted}
+          <HeaderButton isDark={isDark} active={conversation.muted ?? false}
             activeColor="red" onClick={() => muteConversation(conversation.id)}
             title={conversation.muted ? 'Ton aktivieren' : 'Stummschalten'}>
             <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">