diff --git a/src/osgPlugins/txp/trpage_readbuf.cpp b/src/osgPlugins/txp/trpage_readbuf.cpp
index dbebf6e46..8cdd2a6a1 100644
--- a/src/osgPlugins/txp/trpage_readbuf.cpp
+++ b/src/osgPlugins/txp/trpage_readbuf.cpp
@@ -667,6 +667,12 @@ trpgrAppFile *trpgrAppFileCache::GetFile(trpgEndian ness,int id,int col,int row)
         }
     }
 
+    if (oldID<0)
+    {
+        // oldID hasn't been set so we haven't found one to reclaim
+        return 0;
+    }
+
 
     // Reclaim this one
     OpenFile &of = files[oldID];