diff --git a/src/browser/atom-application.coffee b/src/browser/atom-application.coffee
index 1142303cf..54f444d0e 100644
--- a/src/browser/atom-application.coffee
+++ b/src/browser/atom-application.coffee
@@ -65,9 +65,6 @@ class AtomApplication
   constructor: (options) ->
     {@resourcePath, @version, @devMode, @safeMode, @socketPath} = options
 
-    # Normalize to make sure drive letter case is consistent on Windows
-    @resourcePath = path.normalize(@resourcePath) if @resourcePath
-
     global.atomApplication = this
 
     @pidsToOpenWindows = {}
diff --git a/src/browser/atom-window.coffee b/src/browser/atom-window.coffee
index 5f9219ead..99b28444f 100644
--- a/src/browser/atom-window.coffee
+++ b/src/browser/atom-window.coffee
@@ -23,9 +23,6 @@ class AtomWindow
     locationsToOpen ?= [{pathToOpen}] if pathToOpen
     locationsToOpen ?= []
 
-    # Normalize to make sure drive letter case is consistent on Windows
-    @resourcePath = path.normalize(@resourcePath) if @resourcePath
-
     options =
       show: false
       title: 'Atom'
diff --git a/src/browser/main.coffee b/src/browser/main.coffee
index fac1191a7..659c97776 100644
--- a/src/browser/main.coffee
+++ b/src/browser/main.coffee
@@ -54,17 +54,20 @@ start = ->
       else
         path.resolve(pathToOpen)
 
-    if args.devMode
-      AtomApplication = require path.join(args.resourcePath, 'src', 'browser', 'atom-application')
-    else
-      AtomApplication = require './atom-application'
+    AtomApplication = require path.join(args.resourcePath, 'src', 'browser', 'atom-application')
 
     AtomApplication.open(args)
     console.log("App load time: #{Date.now() - global.shellStartTime}ms") unless args.test
 
-global.devResourcePath = process.env.ATOM_DEV_RESOURCE_PATH ? path.join(app.getHomeDir(), 'github', 'atom')
-# Normalize to make sure drive letter case is consistent on Windows
-global.devResourcePath = path.normalize(global.devResourcePath) if global.devResourcePath
+normalizeDriveLetterName = (filePath) ->
+  if process.platform is 'win32'
+    filePath.replace /^([a-z]):/, ([driveLetter]) -> driveLetter.toUpperCase() + ":"
+  else
+    filePath
+
+global.devResourcePath = normalizeDriveLetterName(
+  process.env.ATOM_DEV_RESOURCE_PATH ? path.join(app.getHomeDir(), 'github', 'atom')
+)
 
 setupCrashReporter = ->
   crashReporter.start(productName: 'Atom', companyName: 'GitHub')
@@ -164,6 +167,8 @@ parseCommandLine = ->
   # explicitly pass it by command line, see http://git.io/YC8_Ew.
   process.env.PATH = args['path-environment'] if args['path-environment']
 
+  resourcePath = normalizeDriveLetterName(resourcePath)
+
   {resourcePath, pathsToOpen, executedFrom, test, version, pidToKillWhenClosed,
    devMode, safeMode, newWindow, specDirectory, logFile, socketPath, profileStartup}