diff --git a/build/win32/mozconfig.vs2010-win64 b/build/win32/mozconfig.vs2010-win64
index ba61c24297..677e78e2ea 100644
--- a/build/win32/mozconfig.vs2010-win64
+++ b/build/win32/mozconfig.vs2010-win64
@@ -22,6 +22,9 @@ export LIB=/c/Program\ Files\ \(x86\)/Windows\ Kits/8.0/Lib/win8/um/x86:${_VSPAT
 ## paths: win8 sdk x86 (32-bit) tools, msvc 10 (32-bit) build toolchain, moz tools  ##
 export PATH="/c/Program Files (x86)/Windows Kits/8.0/bin/x86:${_VSPATH}/Common7/IDE:${_VSPATH}/VC/BIN:${_VSPATH}/Common7/Tools:${_VSPATH}/VC/VCPackages:/c/mozilla-build/moztools:${PATH}"
 
+## WindowsSDKDir ##
+export WINDOWSSDKDIR="/c/Program Files (x86)/Windows Kits/8.0/"
+
 . $topsrcdir/build/mozconfig.vs2010-common
 
 mk_export_correct_style LIB
diff --git a/build/win64/mozconfig.vs2010 b/build/win64/mozconfig.vs2010
index c9d925169b..beca1731df 100644
--- a/build/win64/mozconfig.vs2010
+++ b/build/win64/mozconfig.vs2010
@@ -19,6 +19,9 @@ export LIB=/c/Program\ Files\ \(x86\)/Windows\ Kits/8.0/Lib/win8/um/x64:${_VSPAT
 ## paths: win8 sdk x64 (64-bit) tools, msvc 10 (64-bit) build toolchain, moz tools  ##
 export PATH="/c/Program Files (x86)/Windows Kits/8.0/bin/x64:${_VSPATH}/Common7/IDE:${_VSPATH}/VC/BIN/amd64:${_VSPATH}/VC/BIN/x86_amd64:${_VSPATH}/VC/BIN:${_VSPATH}/Common7/Tools:${_VSPATH}/VC/VCPackages:${PATH}"
 
+## WindowsSDKDir ##
+export WINDOWSSDKDIR="/c/Program Files (x86)/Windows Kits/8.0/"
+
 # Use 32bit linker for PGO crash bug.
 # https://connect.microsoft.com/VisualStudio/feedback/details/686117/
 if [ -f /c/PROGRA~2/MICROS~2.0/VC/BIN/x86_amd64/link.exe ]; then