--- a/toolkit/xre/nsAppRunner.cpp
+++ b/toolkit/xre/nsAppRunner.cpp
@@ -15,17 +15,16 @@
 #include "mozilla/MemoryChecking.h"
 #include "mozilla/Poison.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/Printf.h"
 #include "mozilla/ScopeExit.h"
 #include "mozilla/Services.h"
 #include "mozilla/Telemetry.h"
 #include "mozilla/intl/LocaleService.h"
-#include "nsNativeCharsetUtils.h"
 
 #include "nsAppRunner.h"
 #include "mozilla/XREAppData.h"
 #include "mozilla/Bootstrap.h"
 #if defined(MOZ_UPDATER) && !defined(MOZ_WIDGET_ANDROID)
 #include "nsUpdateDriver.h"
 #endif
 #include "ProfileReset.h"
@@ -2504,19 +2503,18 @@ SelectProfile(nsIProfileLock* *aResult, 
     rv = NS_ERROR_ABORT;
     aProfileSvc->Flush();
 
     // XXXben need to ensure prefs.js exists here so the tinderboxes will
     //        not go orange.
     nsCOMPtr<nsIFile> prefsJSFile;
     profile->GetRootDir(getter_AddRefs(prefsJSFile));
     prefsJSFile->AppendNative(NS_LITERAL_CSTRING("prefs.js"));
-    nsAutoCString pathStr;
-    prefsJSFile->GetNativePath(pathStr);
-    PR_fprintf(PR_STDERR, "Success: created profile '%s' at '%s'\n", arg, pathStr.get());
+    PR_fprintf(PR_STDERR, "Success: created profile '%s' at '%s'\n", arg,
+               prefsJSFile->DisplayPath().get());
     bool exists;
     prefsJSFile->Exists(&exists);
     if (!exists) {
       // Ignore any errors; we're about to return NS_ERROR_ABORT anyway.
       Unused << prefsJSFile->Create(nsIFile::NORMAL_FILE_TYPE, 0644);
     }
     // XXXdarin perhaps 0600 would be better?
 
@@ -2759,36 +2757,44 @@ CheckCompatibility(nsIFile* aProfileDir,
   if (NS_FAILED(rv) || !aOSABI.Equals(buf))
     return false;
 
   rv = parser.GetString("Compatibility", "LastPlatformDir", buf);
   if (NS_FAILED(rv))
     return false;
 
   nsCOMPtr<nsIFile> lf;
-  rv = NS_NewNativeLocalFile(buf, false,
+  rv = NS_NewNativeLocalFile(EmptyCString(), false,
                              getter_AddRefs(lf));
   if (NS_FAILED(rv))
     return false;
 
+  rv = lf->SetPersistentDescriptor(buf);
+  if (NS_FAILED(rv))
+    return false;
+
   bool eq;
   rv = lf->Equals(aXULRunnerDir, &eq);
   if (NS_FAILED(rv) || !eq)
     return false;
 
   if (aAppDir) {
     rv = parser.GetString("Compatibility", "LastAppDir", buf);
     if (NS_FAILED(rv))
       return false;
 
-    rv = NS_NewNativeLocalFile(buf, false,
+    rv = NS_NewNativeLocalFile(EmptyCString(), false,
                                getter_AddRefs(lf));
     if (NS_FAILED(rv))
       return false;
 
+    rv = lf->SetPersistentDescriptor(buf);
+    if (NS_FAILED(rv))
+      return false;
+
     rv = lf->Equals(aAppDir, &eq);
     if (NS_FAILED(rv) || !eq)
       return false;
   }
 
   // If we see this flag, caches are invalid.
   rv = parser.GetString("Compatibility", "InvalidateCaches", buf);
   *aCachesOK = (NS_FAILED(rv) || !buf.EqualsLiteral("1"));
@@ -2818,21 +2824,21 @@ WriteVersion(nsIFile* aProfileDir, const
 {
   nsCOMPtr<nsIFile> file;
   aProfileDir->Clone(getter_AddRefs(file));
   if (!file)
     return;
   file->AppendNative(FILE_COMPATIBILITY_INFO);
 
   nsAutoCString platformDir;
-  aXULRunnerDir->GetNativePath(platformDir);
+  Unused << aXULRunnerDir->GetPersistentDescriptor(platformDir);
 
   nsAutoCString appDir;
   if (aAppDir)
-    aAppDir->GetNativePath(appDir);
+    Unused << aAppDir->GetPersistentDescriptor(appDir);
 
   PRFileDesc *fd;
   nsresult rv =
     file->OpenNSPRFileDesc(PR_WRONLY | PR_CREATE_FILE | PR_TRUNCATE, 0600, &fd);
   if (NS_FAILED(rv)) {
     NS_ERROR("could not create output stream");
     return;
   }
@@ -4512,25 +4518,25 @@ XREMain::XRE_mainRun()
       }
 
       // Need to write out the fact that the profile has been removed, the new profile
       // renamed, and potentially that the selected/default profile changed.
       mProfileSvc->Flush();
     }
   }
 
-  if (NS_IsNativeUTF8()) {
+#ifndef XP_WIN
     nsCOMPtr<nsIFile> profileDir;
     nsAutoCString path;
     rv = mDirProvider.GetProfileStartupDir(getter_AddRefs(profileDir));
     if (NS_SUCCEEDED(rv) && NS_SUCCEEDED(profileDir->GetNativePath(path)) && !IsUTF8(path)) {
       PR_fprintf(PR_STDERR, "Error: The profile path is not valid UTF-8. Unable to continue.\n");
       return NS_ERROR_FAILURE;
     }
-  }
+#endif
 
   // Initialize user preferences before notifying startup observers so they're
   // ready in time for early consumers, such as the component loader.
   mDirProvider.InitializeUserPrefs();
 
   {
     nsCOMPtr<nsIObserver> startupNotifier
       (do_CreateInstance(NS_APPSTARTUPNOTIFIER_CONTRACTID, &rv));