diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 8c4b1312cdb..280b8203ff4 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -1891,7 +1891,7 @@ namespace ts {
     export function getExternalModuleNameFromPath(host: EmitHost, fileName: string): string {
         const getCanonicalFileName = (f: string) => host.getCanonicalFileName(f);
         const dir = toPath(host.getCommonSourceDirectory(), host.getCurrentDirectory(), getCanonicalFileName);
-        const filePath = toPath(fileName, host.getCurrentDirectory(), getCanonicalFileName);
+        const filePath = getNormalizedAbsolutePath(fileName, host.getCurrentDirectory());
         const relativePath = getRelativePathToDirectoryOrUrl(dir, filePath, dir, getCanonicalFileName, /*isAbsolutePathAnUrl*/ false);
         return removeFileExtension(relativePath);
     }
diff --git a/tests/baselines/reference/commonSourceDir5.js b/tests/baselines/reference/commonSourceDir5.js
index 8bb11fec583..7a43aba254e 100644
--- a/tests/baselines/reference/commonSourceDir5.js
+++ b/tests/baselines/reference/commonSourceDir5.js
@@ -16,17 +16,17 @@ export var pi = Math.PI;
 export var y = x * i;
 
 //// [concat.js]
-define("b:/baz", ["require", "exports", "a:/bar", "a:/foo"], function (require, exports, bar_1, foo_1) {
+define("B:/baz", ["require", "exports", "A:/bar", "A:/foo"], function (require, exports, bar_1, foo_1) {
     "use strict";
     exports.pi = Math.PI;
     exports.y = bar_1.x * foo_1.i;
 });
-define("a:/foo", ["require", "exports", "b:/baz"], function (require, exports, baz_1) {
+define("A:/foo", ["require", "exports", "B:/baz"], function (require, exports, baz_1) {
     "use strict";
     exports.i = Math.sqrt(-1);
     exports.z = baz_1.pi * baz_1.pi;
 });
-define("a:/bar", ["require", "exports", "a:/foo"], function (require, exports, foo_2) {
+define("A:/bar", ["require", "exports", "A:/foo"], function (require, exports, foo_2) {
     "use strict";
     exports.x = foo_2.z + foo_2.z;
 });
diff --git a/tests/baselines/reference/getEmitOutputSingleFile2.baseline b/tests/baselines/reference/getEmitOutputSingleFile2.baseline
index 8d7b4662187..21e28eb7feb 100644
--- a/tests/baselines/reference/getEmitOutputSingleFile2.baseline
+++ b/tests/baselines/reference/getEmitOutputSingleFile2.baseline
@@ -23,7 +23,7 @@ declare class Foo {
     x: string;
     y: number;
 }
-declare module "inputfile3" {
+declare module "inputFile3" {
     export var foo: number;
     export var bar: string;
 }