diff --git a/src/protocol/parser/mod.rs b/src/protocol/parser/mod.rs
index 8f1500639951df5c37527325b710f7e2f3e88097..b3c7dd4b763992e145130a42b861333a4122ae3a 100644
--- a/src/protocol/parser/mod.rs
+++ b/src/protocol/parser/mod.rs
@@ -327,7 +327,13 @@ impl Parser {
         // Make sure directory exists
         let path = Path::new(&base_path);
         if !path.exists() {
-            return Err(format!("std lib root directory '{}' does not exist", base_path));
+            let from_env_message = if from_env {
+                format!(" (retrieved from the environment variable '{}')", REOWOLF_PATH_ENV)
+            } else {
+                String::new()
+            };
+
+            return Err(format!("std lib root directory '{}'{} does not exist", base_path, from_env_message));
         }
 
         // Try to load all standard library files. We might need a more unified