diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index dfe6317e250..f24d5e3e0cb 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -922,7 +922,7 @@ namespace ts {
                 if (result && isInExternalModule && (meaning & SymbolFlags.Value) === SymbolFlags.Value) {
                     const decls = result.declarations;
                     if (decls && decls.length === 1 && decls[0].kind === SyntaxKind.NamespaceExportDeclaration) {
-                        error(errorLocation, Diagnostics.Identifier_0_must_be_imported_from_a_module, name);
+                        error(errorLocation, Diagnostics._0_refers_to_a_UMD_global_but_the_current_file_is_a_module_Consider_adding_an_import_instead, name);
                     }
                 }
             }
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 58c0e6ee3f2..b99a1a91b8e 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -1923,7 +1923,7 @@
         "category": "Error",
         "code": 2685
     },
-    "Identifier '{0}' must be imported from a module": {
+    "'{0}' refers to a UMD global, but the current file is a module. Consider adding an import instead.": {
         "category": "Error",
         "code": 2686
     },