diff --git a/openbr/plugins/output.cpp b/openbr/plugins/output.cpp
index d431fd1..35de866 100644
--- a/openbr/plugins/output.cpp
+++ b/openbr/plugins/output.cpp
@@ -269,7 +269,8 @@ class evalOutput : public MatrixOutput
 
     ~evalOutput()
     {
-        Evaluate(data, BEE::makeMask(targetFiles, queryFiles), "");
+        if (data.data)
+            Evaluate(data, BEE::makeMask(targetFiles, queryFiles), "");
     }
 };