diff --git a/pom.xml b/pom.xml
index 7d32756..032c198 100644
--- a/pom.xml
+++ b/pom.xml
@@ -6,7 +6,7 @@
     <modelVersion>4.0.0</modelVersion>
     <groupId>io.github.mooy1</groupId>
     <artifactId>InfinityLib</artifactId>
-    <version>1.3.7</version>
+    <version>1.3.8</version>
 
     <properties>
         <maven.compiler.source>1.8</maven.compiler.source>
diff --git a/src/main/java/io/github/mooy1/infinitylib/machines/MachineRecipeType.java b/src/main/java/io/github/mooy1/infinitylib/machines/MachineRecipeType.java
index 0895dce..a8e59ce 100644
--- a/src/main/java/io/github/mooy1/infinitylib/machines/MachineRecipeType.java
+++ b/src/main/java/io/github/mooy1/infinitylib/machines/MachineRecipeType.java
@@ -8,6 +8,7 @@
 
 import lombok.Getter;
 
+import org.apache.commons.lang.Validate;
 import org.bukkit.inventory.ItemStack;
 
 import io.github.mooy1.infinitylib.core.AbstractAddon;
@@ -25,6 +26,10 @@ public MachineRecipeType(String key, ItemStack item) {
 
     @Override
     public void register(ItemStack[] recipe, ItemStack result) {
+        if (recipe == null) return;
+        for (ItemStack stack : recipe) {
+            if (stack == null) return;
+        }
         callbacks.forEach(c -> c.accept(recipe, result));
         recipes.put(recipe, result);
     }