new file mode 100644
--- /dev/null
+++ b/mail/config/tooltool-manifests/win32/check-sync-exceptions
@@ -0,0 +1,4 @@
+# Bug 1387227
+# mozilla-central started using xz to compress mar files. comm-central's
+# windows buildbots don't install it, so install it via tooltool
+releng.manifest

--- a/mail/config/tooltool-manifests/win32/releng.manifest
+++ b/mail/config/tooltool-manifests/win32/releng.manifest
@@ -32,10 +32,17 @@
   },
   {
     "version": "clang 5.0pre/r293859",
     "size": 309009013,
     "digest": "cd3ed31acefd185f441632158dde73538c62bab7ebf2a8ec630985ab345938ec522983721ddb1bead1de22d5ac1571d50a958ae002364d739f2a78c6e7244222",
     "algorithm": "sha512",
     "filename": "clang.tar.bz2",
     "unpack": true
+  },
+  {
+    "size": 216733,
+    "digest": "7debd8ce46955eae345ebdf2ee6df3bfc3f3a547af1306f7fb099e38750f5ed9412af7155017574fc796f2bb8f37b5b7c4f91d838fa3dc422a776c230ba2d64b",
+    "algorithm": "sha512",
+    "filename": "xz.tar.bz2",
+    "unpack": true
   }
 ]

new file mode 100644
--- /dev/null
+++ b/mail/config/tooltool-manifests/win64/check-sync-exceptions
@@ -0,0 +1,4 @@
+# Bug 1387227
+# mozilla-central started using xz to compress mar files. comm-central's
+# windows buildbots don't install it, so install it via tooltool
+releng.manifest

--- a/mail/config/tooltool-manifests/win64/releng.manifest
+++ b/mail/config/tooltool-manifests/win64/releng.manifest
@@ -33,10 +33,17 @@
   },
   {
     "version": "clang 5.0pre/r293859",
     "size": 313862839,
     "digest": "44dee70d525ea93952af27f943d1cc773311970c31d971d2bc2e3437cce0c899f3a03ddd8e42e86f1b4fd9ab1c4bc1767cdb0406eb4b3934ae4fc272dab830dc",
     "algorithm": "sha512",
     "filename": "clang.tar.bz2",
     "unpack": true
+  },
+  {
+    "size": 216733,
+    "digest": "7debd8ce46955eae345ebdf2ee6df3bfc3f3a547af1306f7fb099e38750f5ed9412af7155017574fc796f2bb8f37b5b7c4f91d838fa3dc422a776c230ba2d64b",
+    "algorithm": "sha512",
+    "filename": "xz.tar.bz2",
+    "unpack": true
   }
 ]