diff --git a/CHANGELOG.md b/CHANGELOG.md
index 14e927d..aee0cfb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -26,6 +26,7 @@ Note to self: See the bottom of this file for the release template text.
      - `moretrees:apple_tree_sapling_ongen` from `apple` to `apple_moretrees`
      - Add `plum` → `plumtree:sapling`
      - Add `holly` ⇒ `hollytree:sapling`
+ - `//replacemix`: Improve error handling to avoid crashes (thanks, Jonathon for reporting via Discord!)
 
 
 ## v1.12: The selection tools update (26th June 2021)
diff --git a/worldeditadditions_commands/commands/replacemix.lua b/worldeditadditions_commands/commands/replacemix.lua
index 085e596..dd5ff77 100644
--- a/worldeditadditions_commands/commands/replacemix.lua
+++ b/worldeditadditions_commands/commands/replacemix.lua
@@ -53,6 +53,9 @@ worldedit.register_command("replacemix", {
 				end
 			end
 		end
+		if not target_node then return false, "Error: No target node specified." end
+		if not last_node_name then return false, "Error: At least 1 replace node must be specified." end
+		
 		if not replace_nodes[last_node_name] then
 			replace_nodes[last_node_name] = 1
 		end