--- tools/update-packaging/make_incremental_update.sh
+++ tools/update-packaging/make_incremental_update.sh
@@ -110,7 +110,7 @@
   # Remove the /
   newdir=$(echo "$newdir" | sed -e 's:\/$::')
 fi
-workdir="$(mktemp -d)"
+workdir=$(cygpath -m "$(mktemp -d)")
 updatemanifestv3="$workdir/updatev3.manifest"
 
 mkdir -p "$workdir"