diff --git a/appveyor.yml b/appveyor.yml
index 7955a4fadf6..5d9b0f6d4ba 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -35,9 +35,6 @@ branches:
   only:
     - master
 
-platform:
-  - x64
-
 cache:
   - .servo -> rust-nightly-date, cargo-commit-hash
   - .cargo -> rust-nightly-date, cargo-commit-hash
diff --git a/python/servo/command_base.py b/python/servo/command_base.py
index b0f62e65061..991915d753d 100644
--- a/python/servo/command_base.py
+++ b/python/servo/command_base.py
@@ -110,10 +110,12 @@ def host_triple():
         os_type = "linux-androideabi"
     elif os_type == "windows":
         # If we are in a Visual Studio environment, use msvc
-        if os.getenv("VSInstallDir") is not None:
+        if os.getenv("PLATFORM") is not None:
             os_type = "pc-windows-msvc"
-        else:
+        elif os.getenv("MSYSTEM") is not None:
             os_type = "pc-windows-gnu"
+        else:
+            os_type = "unknown"
     elif os_type.startswith("mingw64_nt-") or os_type.startswith("cygwin_nt-"):
         os_type = "pc-windows-gnu"
     elif os_type == "freebsd":