diff --git a/mozilla/tools/build-environment/win32/guess-msvc.bat b/mozilla/tools/build-environment/win32/guess-msvc.bat
index eb1823a6194..7411a3250f7 100755
--- a/mozilla/tools/build-environment/win32/guess-msvc.bat
+++ b/mozilla/tools/build-environment/win32/guess-msvc.bat
@@ -1,5 +1,13 @@
 @ECHO OFF
 
+set CYGWIN=
+if not defined MOZ_NO_RESET_PATH (
+    set PATH=%SystemRoot%\System32;%SystemRoot%;%SystemRoot%\System32\Wbem
+)
+
+SET INCLUDE=
+SET LIB=
+
 SET MSVCROOTKEY=HKLM\SOFTWARE\Microsoft\VisualStudio
 SET MSVC6KEY=%MSVCROOTKEY%\6.0\Setup\Microsoft Visual C++
 SET MSVC71KEY=%MSVCROOTKEY%\7.1\Setup\VC
diff --git a/mozilla/tools/build-environment/win32/packageit.py b/mozilla/tools/build-environment/win32/packageit.py
index 73653df83a9..9c242003181 100644
--- a/mozilla/tools/build-environment/win32/packageit.py
+++ b/mozilla/tools/build-environment/win32/packageit.py
@@ -49,7 +49,8 @@ environ["MOZ_SRCDIR"] = sourcedir
 print("Source file location: " + sourcedir)
 print("Output location: " + stagedir)
 
-rmtree(join(stagedir, "mozilla-build"))
+if exists(join(stagedir, "mozilla-build")):
+    rmtree(join(stagedir, "mozilla-build"))
 
 check_call([join(sourcedir, "7z442.exe"),
             "/D=" + join(stagedir, "mozilla-build", "7zip")])
diff --git a/mozilla/tools/build-environment/win32/start-msvc6.bat b/mozilla/tools/build-environment/win32/start-msvc6.bat
index fbd25ee8b79..b8be612c2e2 100755
--- a/mozilla/tools/build-environment/win32/start-msvc6.bat
+++ b/mozilla/tools/build-environment/win32/start-msvc6.bat
@@ -20,9 +20,6 @@ if "%VC6DIR%"=="Not Found" (
 REM For MSVC6, we use the "old" non-static moztools
 set MOZ_TOOLS=%MOZILLABUILD%\moztools-180compat
 
-SET INCLUDE=
-SET LIB=
-
 rem append moztools to PATH
 SET PATH=%PATH%;%MOZ_TOOLS%\bin
 
diff --git a/mozilla/tools/build-environment/win32/start-msvc71.bat b/mozilla/tools/build-environment/win32/start-msvc71.bat
index cd6438d714d..0035b1018ab 100755
--- a/mozilla/tools/build-environment/win32/start-msvc71.bat
+++ b/mozilla/tools/build-environment/win32/start-msvc71.bat
@@ -20,9 +20,6 @@ if "%VC71DIR%"=="Not Found" (
 REM Use the "new" moztools-static
 set MOZ_TOOLS=%MOZILLABUILD%\moztools
 
-SET INCLUDE=
-SET LIB=
-
 rem append moztools to PATH
 SET PATH=%PATH%;%MOZ_TOOLS%\bin
 
diff --git a/mozilla/tools/build-environment/win32/start-msvc8.bat b/mozilla/tools/build-environment/win32/start-msvc8.bat
index f8665eea4ef..112089515c6 100755
--- a/mozilla/tools/build-environment/win32/start-msvc8.bat
+++ b/mozilla/tools/build-environment/win32/start-msvc8.bat
@@ -20,9 +20,6 @@ if "%VC8DIR%"=="Not Found" (
 REM Use the "new" moztools-static
 set MOZ_TOOLS=%MOZILLABUILD%\moztools
 
-SET INCLUDE=
-SET LIB=
-
 rem append moztools to PATH
 SET PATH=%PATH%;%MOZ_TOOLS%\bin