diff --git a/appveyor.yml b/appveyor.yml
index 4c64f29..04ed58e 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -16,7 +16,7 @@
     build_script:
       ps: "C:\\msys64\\usr\\bin\\bash -lc @\"\n
       pacman -S --quiet --noconfirm --needed re2c 2>&1\n
-      sed -i 's|cmd /c $ar cqs $out.tmp $in && move /Y $out.tmp $out|$ar crs $out $in|g' configure.py\n
+      sed -i 's|cmd /c `$ar cqs `$out.tmp `$in \\&\\& move /Y `$out.tmp `$out|`$ar crs `$out `$in|g' configure.py\n
       ./configure.py --bootstrap --platform mingw 2>&1\n
       ./ninja all\n
       ./ninja_test 2>&1\n