diff --git a/changelog.txt b/changelog.txt
index 9da35be..c372364 100644
--- a/changelog.txt
+++ b/changelog.txt
@@ -1,3 +1,9 @@
+---------------------------------------------------------------------------------------------------
+Version: 0.5.1
+Date: 05. 09. 2020
+  Bugfixes:
+    - Fix crash on selecting new blueprint book
+
 ---------------------------------------------------------------------------------------------------
 Version: 0.5.0
 Date: 31. 01. 2020
diff --git a/info.json b/info.json
index 8c01dce..567dd65 100644
--- a/info.json
+++ b/info.json
@@ -1,6 +1,6 @@
 {
     "name": "BlueprintExtensions",
-    "version": "0.5.0",
+    "version": "0.5.1",
     "title": "Blueprint Extensions",
     "author": "Dewin",
     "contact": "https://github.com/dewiniaid/BlueprintExtensions",
diff --git a/util.lua b/util.lua
index fadba7f..e33734c 100644
--- a/util.lua
+++ b/util.lua
@@ -8,7 +8,11 @@ function Util.get_blueprint(bp)
         return nil
     end
     if bp.is_blueprint_book and bp.active_index then
-        return Util.get_blueprint(bp.get_inventory(defines.inventory.item_main)[bp.active_index])
+        local inventory = bp.get_inventory(defines.inventory.item_main)
+        if inventory.get_item_count() == 0 then
+            return nil
+        end
+        return Util.get_blueprint(inventory[bp.active_index])
     end
     if bp.is_blueprint then
         return bp