diff --git a/crates/compiler/builtins/src/bitcode.rs b/crates/compiler/builtins/src/bitcode.rs
index 94ef5be80d..f94a5aa86b 100644
--- a/crates/compiler/builtins/src/bitcode.rs
+++ b/crates/compiler/builtins/src/bitcode.rs
@@ -3,10 +3,10 @@ use roc_target::TargetInfo;
 use roc_utils::get_lib_path;
 use std::ops::Index;
 
+const LIB_DIR_ERROR: &'static str = "Failed to find the lib directory. Did you copy the roc binary without also copying the lib directory?\nIf you built roc from source, the lib dir should be in target/release.\nIf not, the lib dir should be included in the release tar.gz file.";
+
 pub fn get_builtins_host_obj_path() -> String {
-    let builtins_host_path = get_lib_path()
-        .expect("Failed to find lib dir.")
-        .join("builtins-host.o");
+    let builtins_host_path = get_lib_path().expect(LIB_DIR_ERROR).join("builtins-host.o");
 
     builtins_host_path
         .into_os_string()
@@ -16,7 +16,7 @@ pub fn get_builtins_host_obj_path() -> String {
 
 pub fn get_builtins_wasm32_obj_path() -> String {
     let builtins_wasm32_path = get_lib_path()
-        .expect("Failed to find lib dir.")
+        .expect(LIB_DIR_ERROR)
         .join("builtins-wasm32.o");
 
     builtins_wasm32_path