diff --git a/mutants/mutant-2/swen90006/machine/Machine.java b/mutants/mutant-2/swen90006/machine/Machine.java
index 9bf57316d1c736ea2bd1c62bd6df3c6c0282f331..eb7249fbb435213fb71a654147ec88aca585d522 100644
--- a/mutants/mutant-2/swen90006/machine/Machine.java
+++ b/mutants/mutant-2/swen90006/machine/Machine.java
@@ -140,7 +140,7 @@ public class Machine
   private void validate_reg(int reg)
     throws InvalidInstructionException
   {
-    if (reg < 0 || reg > MAX_REG) {
+    if (reg < 0 || reg >= MAX_REG) {
       throw new InvalidInstructionException();
     }
   }