diff --git a/hmmlconv/hmmlconv.c b/hmmlconv/hmmlconv.c
index 722087d..24c1c99 100644
--- a/hmmlconv/hmmlconv.c
+++ b/hmmlconv/hmmlconv.c
@@ -116,7 +116,7 @@ char *InPlaceUnescape(char *In)
         *Out++ = *In++;
     }
 
-    if(*In != '"')
+    if(*In != '"' || In[1] != '\0')
     {
         return NULL;
     }