--- a/mailnews/base/src/nsMsgDBView.cpp
+++ b/mailnews/base/src/nsMsgDBView.cpp
@@ -6965,28 +6965,32 @@ nsresult nsMsgDBView::SetThreadIgnored(n
   NoteChange(threadIndex, 1, nsMsgViewNotificationCode::changed);
   if (ignored)
   {
     nsTArray<nsMsgKey> idsMarkedRead;
 
     MarkThreadRead(thread, threadIndex, idsMarkedRead, true);
     CollapseByIndex(threadIndex, nullptr);
   }
+
+  if (!m_db)
+    return NS_ERROR_FAILURE;
   return m_db->MarkThreadIgnored(thread, m_keys[threadIndex], ignored, this);
 }
 
 nsresult nsMsgDBView::SetSubthreadKilled(nsIMsgDBHdr *header, nsMsgViewIndex msgIndex, bool ignored)
 {
   if (!IsValidIndex(msgIndex))
     return NS_MSG_INVALID_DBVIEW_INDEX;
 
   NoteChange(msgIndex, 1, nsMsgViewNotificationCode::changed);
-  nsresult rv;
-
-  rv = m_db->MarkHeaderKilled(header, ignored, this);
+
+  if (!m_db)
+    return NS_ERROR_FAILURE;
+  nsresult rv = m_db->MarkHeaderKilled(header, ignored, this);
   NS_ENSURE_SUCCESS(rv, rv);
 
   if (ignored)
   {
     nsCOMPtr <nsIMsgThread> thread;
     nsresult rv;
     rv = GetThreadContainingMsgHdr(header, getter_AddRefs(thread));
     if (NS_FAILED(rv))