diff --git a/spec/Bundle.ts b/spec/Bundle.ts
index ac9d321..368c28d 100644
--- a/spec/Bundle.ts
+++ b/spec/Bundle.ts
@@ -83,7 +83,7 @@ describe("Bundle", () => {
 
 				expect(() =>
 					bundle.addBuffer("icon.png", Buffer.alloc(0)),
-				).toThrowError(Error, "Cannot add file. Bundle is closed.");
+				).toThrowError(Error, Messages.BUNDLE.CLOSED);
 			});
 		});
 
diff --git a/src/messages.ts b/src/messages.ts
index eebda27..e8b56d0 100644
--- a/src/messages.ts
+++ b/src/messages.ts
@@ -77,7 +77,7 @@ export const MODELS = {
 
 export const BUNDLE = {
 	MIME_TYPE_MISSING: "Cannot build Bundle. MimeType is missing",
-	CLOSED: "Cannot add file. Bundle is closed.",
+	CLOSED: "Cannot add file or set property. Bundle is closed.",
 } as const;
 
 export const FROM = {