diff --git a/src/main/java/io/github/thebusybiscuit/sensibletoolbox/api/gui/InventoryGUI.java b/src/main/java/io/github/thebusybiscuit/sensibletoolbox/api/gui/InventoryGUI.java
index 3108881b..53e03fb6 100644
--- a/src/main/java/io/github/thebusybiscuit/sensibletoolbox/api/gui/InventoryGUI.java
+++ b/src/main/java/io/github/thebusybiscuit/sensibletoolbox/api/gui/InventoryGUI.java
@@ -156,6 +156,11 @@ public interface InventoryGUI {
      */
     void show(Player player);
 
+    /**
+     * Hides this GUI from all players
+     */
+    void hideForAll();
+
     /**
      * Hide this GUI from the given player (pop it down)
      *
diff --git a/src/main/java/io/github/thebusybiscuit/sensibletoolbox/api/items/BaseSTBMachine.java b/src/main/java/io/github/thebusybiscuit/sensibletoolbox/api/items/BaseSTBMachine.java
index 875474d4..92718f27 100644
--- a/src/main/java/io/github/thebusybiscuit/sensibletoolbox/api/items/BaseSTBMachine.java
+++ b/src/main/java/io/github/thebusybiscuit/sensibletoolbox/api/items/BaseSTBMachine.java
@@ -584,6 +584,10 @@ public void onBlockRegistered(Location location, boolean isPlacing) {
 
     @Override
     public void onBlockUnregistered(Location loc) {
+        // Machines broken while viewed allow items to be taken out.
+        // We need to close the inventories if opened.
+        getGUI().hideForAll();
+
         getGUI().ejectItems(getInputSlots());
         getGUI().ejectItems(getOutputSlots());
         getGUI().ejectItems(getUpgradeSlots());
diff --git a/src/main/java/io/github/thebusybiscuit/sensibletoolbox/core/gui/STBInventoryGUI.java b/src/main/java/io/github/thebusybiscuit/sensibletoolbox/core/gui/STBInventoryGUI.java
index 9170e8da..95faa270 100644
--- a/src/main/java/io/github/thebusybiscuit/sensibletoolbox/core/gui/STBInventoryGUI.java
+++ b/src/main/java/io/github/thebusybiscuit/sensibletoolbox/core/gui/STBInventoryGUI.java
@@ -37,6 +37,8 @@
 import me.desht.dhutils.Debugger;
 import me.desht.dhutils.text.LogUtils;
 
+import javax.annotation.Nonnull;
+
 public class STBInventoryGUI implements InventoryGUI {
 
     // some handy stock textures
@@ -103,6 +105,10 @@ private static void setOpenGUI(Player player, InventoryGUI gui) {
         }
     }
 
+    private boolean hasOpenGUI(@Nonnull Player player) {
+        return getOpenGUI(player) == null;
+    }
+
     @Override
     public void addGadget(ClickableGadget gadget) {
         int slot = gadget.getSlot();
@@ -197,10 +203,19 @@ public void show(Player player) {
                 monitor.doRepaint();
             }
         }
-        Debugger.getInstance().debug(player.getName() + " opened GUI for " + getOwningItem());
-        setOpenGUI(player, this);
-        listener.onGUIOpened(player);
-        player.openInventory(inventory);
+        if (hasOpenGUI(player)) {
+            Debugger.getInstance().debug(player.getName() + " opened GUI for " + getOwningItem());
+            setOpenGUI(player, this);
+            listener.onGUIOpened(player);
+            player.openInventory(inventory);
+        }
+    }
+
+    @Override
+    public void hideForAll() {
+        for (HumanEntity player : new ArrayList<>(inventory.getViewers())) {
+            hide((Player) player);
+        }
     }
 
     @Override