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Last active April 11, 2024 12:11
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Download MSVC compiler/linker & Windows SDK without installing full Visual Studio

This downloads standalone 64-bit MSVC compiler, linker & other tools, also headers/libraries from Windows SDK into portable folder, without installing Visual Studio. Has bare minimum components - no UWP/Store/WindowsRT stuff, just files & tools for 64-bit native desktop app development.

Run python.exe and it will download output into msvc folder. By default it will download latest available MSVC & Windows SDK - currently v14.32.17.2 and v10.0.22621.0.

You can list available versions with python.exe --show-versions and then pass versions you want with --msvc-version and --sdk-version arguments.

To use cl.exe/link.exe from output folder, first run setup.bat - after that PATH/INCLUDE/LIB env variables will be setup to use all the tools as usual. You can also use clang-cl.exe with these includes & libraries.

To use clang-cl.exe without running setup.bat, pass extra /winsysroot msvc argument (msvc is folder name where output is stored).

#!/usr/bin/env python3
import io
import os
import sys
import json
import shutil
import hashlib
import zipfile
import tempfile
import argparse
import subprocess
import urllib.request
import urllib.error
from pathlib import Path
OUTPUT = Path("msvc") # output folder
# other architectures may work or may not - not really tested
HOST = "x64" # or x86
TARGET = "x64" # or x86, arm, arm64
ssl_context = None
def download(url):
with urllib.request.urlopen(url, context=ssl_context) as res:
def download_progress(url, check, name, f):
data = io.BytesIO()
with urllib.request.urlopen(url, context=ssl_context) as res:
total = int(res.headers["Content-Length"])
size = 0
while True:
block =<<20)
if not block:
size += len(block)
perc = size * 100 // total
print(f"\r{name} ... {perc}%", end="")
data = data.getvalue()
digest = hashlib.sha256(data).hexdigest()
if check.lower() != digest:
exit(f"Hash mismatch for f{pkg}")
return data
# super crappy msi format parser just to find required .cab files
def get_msi_cabs(msi):
index = 0
while True:
index = msi.find(b".cab", index+4)
if index < 0:
yield msi[index-32:index+4].decode("ascii")
def first(items, cond):
return next(item for item in items if cond(item))
### parse command-line arguments
ap = argparse.ArgumentParser()
ap.add_argument("--show-versions", action="store_true", help="Show available MSVC and Windows SDK versions")
ap.add_argument("--accept-license", action="store_true", help="Automatically accept license")
ap.add_argument("--msvc-version", help="Get specific MSVC version")
ap.add_argument("--sdk-version", help="Get specific Windows SDK version")
ap.add_argument("--preview", action="store_true", help="Use preview channel for Preview versions")
args = ap.parse_args()
### get main manifest
manifest = json.loads(download(URL))
except urllib.error.URLError as err:
import ssl
if isinstance(err.args[0], ssl.SSLCertVerificationError):
# for more info about Python & issues with Windows certificates see
print("ERROR: ssl certificate verification error")
import certifi
except ModuleNotFoundError:
print("ERROR: please install 'certifi' package to use Mozilla certificates")
print("ERROR: or update your Windows certs, see instructions here:")
print("NOTE: retrying with certifi certificates")
ssl_context = ssl.create_default_context(cafile=certifi.where())
manifest = json.loads(download(URL))
### download VS manifest
ITEM_NAME = "Microsoft.VisualStudio.Manifests.VisualStudioPreview" if args.preview else "Microsoft.VisualStudio.Manifests.VisualStudio"
vs = first(manifest["channelItems"], lambda x: x["id"] == ITEM_NAME)
payload = vs["payloads"][0]["url"]
vsmanifest = json.loads(download(payload))
### find MSVC & WinSDK versions
packages = {}
for p in vsmanifest["packages"]:
packages.setdefault(p["id"].lower(), []).append(p)
msvc = {}
sdk = {}
for pid,p in packages.items():
if pid.startswith("Microsoft.VisualStudio.Component.VC.".lower()) and pid.endswith(".x86.x64".lower()):
pver = ".".join(pid.split(".")[4:6])
if pver[0].isnumeric():
msvc[pver] = pid
elif pid.startswith("Microsoft.VisualStudio.Component.Windows10SDK.".lower()) or \
pver = pid.split(".")[-1]
if pver.isnumeric():
sdk[pver] = pid
if args.show_versions:
print("MSVC versions:", " ".join(sorted(msvc.keys())))
print("Windows SDK versions:", " ".join(sorted(sdk.keys())))
msvc_ver = args.msvc_version or max(sorted(msvc.keys()))
sdk_ver = args.sdk_version or max(sorted(sdk.keys()))
if msvc_ver in msvc:
msvc_pid = msvc[msvc_ver]
msvc_ver = ".".join(msvc_pid.split(".")[4:-2])
exit(f"Unknown MSVC version: f{args.msvc_version}")
if sdk_ver in sdk:
sdk_pid = sdk[sdk_ver]
exit(f"Unknown Windows SDK version: f{args.sdk_version}")
print(f"Downloading MSVC v{msvc_ver} and Windows SDK v{sdk_ver}")
### agree to license
tools = first(manifest["channelItems"], lambda x: x["id"] == "Microsoft.VisualStudio.Product.BuildTools")
resource = first(tools["localizedResources"], lambda x: x["language"] == "en-us")
license = resource["license"]
if not args.accept_license:
accept = input(f"Do you accept Visual Studio license at {license} [Y/N] ? ")
if not accept or accept[0].lower() != "y":
total_download = 0
### download MSVC
msvc_packages = [
# MSVC binaries
# MSVC headers
# MSVC libs
# MSVC runtime source
# MSVC redist
for pkg in msvc_packages:
p = first(packages[pkg], lambda p: p.get("language") in (None, "en-US"))
for payload in p["payloads"]:
with tempfile.TemporaryFile() as f:
data = download_progress(payload["url"], payload["sha256"], pkg, f)
total_download += len(data)
with zipfile.ZipFile(f) as z:
for name in z.namelist():
if name.startswith("Contents/"):
out = OUTPUT / Path(name).relative_to("Contents")
out.parent.mkdir(parents=True, exist_ok=True)
### download Windows SDK
sdk_packages = [
# Windows SDK tools (like rc.exe & mt.exe)
f"Windows SDK for Windows Store Apps Tools-x86_en-us.msi",
# Windows SDK headers
f"Windows SDK for Windows Store Apps Headers-x86_en-us.msi",
f"Windows SDK Desktop Headers x86-x86_en-us.msi",
# Windows SDK libs
f"Windows SDK for Windows Store Apps Libs-x86_en-us.msi",
f"Windows SDK Desktop Libs {TARGET}-x86_en-us.msi",
# CRT headers & libs
f"Universal CRT Headers Libraries and Sources-x86_en-us.msi",
# CRT redist
#"Universal CRT Redistributable-x86_en-us.msi",
with tempfile.TemporaryDirectory() as d:
dst = Path(d)
sdk_pkg = packages[sdk_pid][0]
sdk_pkg = packages[first(sdk_pkg["dependencies"], lambda x: True).lower()][0]
msi = []
cabs = []
# download msi files
for pkg in sdk_packages:
payload = first(sdk_pkg["payloads"], lambda p: p["fileName"] == f"Installers\\{pkg}")
msi.append(dst / pkg)
with open(dst / pkg, "wb") as f:
data = download_progress(payload["url"], payload["sha256"], pkg, f)
total_download += len(data)
cabs += list(get_msi_cabs(data))
# download .cab files
for pkg in cabs:
payload = first(sdk_pkg["payloads"], lambda p: p["fileName"] == f"Installers\\{pkg}")
with open(dst / pkg, "wb") as f:
data = download_progress(payload["url"], payload["sha256"], pkg, f)
total_download += len(data)
print("Unpacking msi files...")
# run msi installers
for m in msi:
subprocess.check_call(["msiexec.exe", "/a", m, "/quiet", "/qn", f"TARGETDIR={OUTPUT.resolve()}"])
### versions
msvcv = list((OUTPUT / "VC/Tools/MSVC").glob("*"))[0].name
sdkv = list((OUTPUT / "Windows Kits/10/bin").glob("*"))[0].name
# place debug CRT runtime files into MSVC folder (not what real Visual Studio installer does... but is reasonable)
dst = OUTPUT / "VC/Tools/MSVC" / msvcv / f"bin/Host{HOST}/{TARGET}"
with tempfile.TemporaryDirectory() as d:
d = Path(d)
pkg = "microsoft.visualcpp.runtimedebug.14"
dbg = first(packages[pkg], lambda p: p["chip"] == HOST)
for payload in dbg["payloads"]:
name = payload["fileName"]
with open(d / name, "wb") as f:
data = download_progress(payload["url"], payload["sha256"], f"{pkg}/{name}", f)
total_download += len(data)
msi = d / first(dbg["payloads"], lambda p: p["fileName"].endswith(".msi"))["fileName"]
with tempfile.TemporaryDirectory() as d2:
subprocess.check_call(["msiexec.exe", "/a", str(msi), "/quiet", "/qn", f"TARGETDIR={d2}"])
for f in first(Path(d2).glob("System*"), lambda x: True).iterdir():
f.replace(dst /
# download DIA SDK and put msdia140.dll file into MSVC folder
with tempfile.TemporaryDirectory() as d:
d = Path(d)
pkg = "microsoft.visualc.140.dia.sdk.msi"
dia = packages[pkg][0]
for payload in dia["payloads"]:
name = payload["fileName"]
with open(d / name, "wb") as f:
data = download_progress(payload["url"], payload["sha256"], f"{pkg}/{name}", f)
total_download += len(data)
msi = d / first(dia["payloads"], lambda p: p["fileName"].endswith(".msi"))["fileName"]
with tempfile.TemporaryDirectory() as d2:
subprocess.check_call(["msiexec.exe", "/a", str(msi), "/quiet", "/qn", f"TARGETDIR={d2}"])
if HOST == "x86": msdia = "msdia140.dll"
elif HOST == "x64": msdia = "amd64/msdia140.dll"
else: exit("unknown")
src = Path(d2) / "Program Files" / "Microsoft Visual Studio 14.0" / "DIA SDK" / "bin" / msdia
src.replace(dst / "msdia140.dll")
### cleanup
shutil.rmtree(OUTPUT / "Common7", ignore_errors=True)
for f in ["Auxiliary", f"lib/{TARGET}/store", f"lib/{TARGET}/uwp"]:
shutil.rmtree(OUTPUT / "VC/Tools/MSVC" / msvcv / f)
for f in OUTPUT.glob("*.msi"):
for f in ["Catalogs", "DesignTime", f"bin/{sdkv}/chpe", f"Lib/{sdkv}/ucrt_enclave"]:
shutil.rmtree(OUTPUT / "Windows Kits/10" / f, ignore_errors=True)
for arch in ["x86", "x64", "arm", "arm64"]:
if arch != TARGET:
shutil.rmtree(OUTPUT / "Windows Kits/10/Lib" / sdkv / "ucrt" / arch)
shutil.rmtree(OUTPUT / "Windows Kits/10/Lib" / sdkv / "um" / arch)
if arch != HOST:
shutil.rmtree(OUTPUT / "Windows Kits/10/bin" / sdkv / arch)
# executable that is collecting & sending telemetry every time cl/link runs
(OUTPUT / "VC/Tools/MSVC" / msvcv / f"bin/Host{HOST}/{TARGET}/vctip.exe").unlink(missing_ok=True)
### setup.bat
SETUP = f"""@echo off
set ROOT=%~dp0
set MSVC_VERSION={msvcv}
set SDK_VERSION={sdkv}
set SDK_INCLUDE=%ROOT%Windows Kits\\10\\Include\\%SDK_VERSION%
set SDK_LIBS=%ROOT%Windows Kits\\10\\Lib\\%SDK_VERSION%
set VCToolsInstallDir=%MSVC_ROOT%\\
set PATH=%MSVC_ROOT%\\bin\\%MSVC_HOST%\\%MSVC_ARCH%;%ROOT%Windows Kits\\10\\bin\\%SDK_VERSION%\\%SDK_ARCH%;%ROOT%Windows Kits\\10\\bin\\%SDK_VERSION%\\%SDK_ARCH%\\ucrt;%PATH%
set INCLUDE=%MSVC_ROOT%\\include;%SDK_INCLUDE%\\ucrt;%SDK_INCLUDE%\\shared;%SDK_INCLUDE%\\um;%SDK_INCLUDE%\\winrt;%SDK_INCLUDE%\\cppwinrt
(OUTPUT / "setup.bat").write_text(SETUP)
print(f"Total downloaded: {total_download>>20} MB")
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AndhikaWB commented Dec 6, 2023

@florianingerl I think the target dir must be full path, not relative path. Try replacing TARGETDIR={d2} with TARGETDIR={Path(d2).resolve()}.

Or just use the original code, install it in C, you can move it to D drive later.

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Works great with cl / link! But clang-cl is unrecognized, even after running the batch script. Any ideas?

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mmozeiko commented Dec 9, 2023

If it says clang-cl.exe is unrecognized then you have not set PATH to where it is installed. Either put folder where clang-cl is in the PATH env variable, or run by specifying absolute path to clang-cl.exe.

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Where is clang-cl.exe supposed to be installed? After running the setup.bat, cl.exe and link.exe are recognized, so I'm not sure env variables is the issue.

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mmozeiko commented Dec 9, 2023

You can install it anywhere. When you run llvm/clang installer then by default it will install in C:\Program Files\LLVM. But during installation you can put any location there - it's up to you where you want it.

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Oh, my bad. I thougth that clang came preinstalled with the packages. So this is just the integration with msvc?

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mmozeiko commented Dec 9, 2023

Right, this downloads MSVC compiler & linker and Windows SDK headers & libs. Not clang. You can install clang from their github releases. It will be able to use Windows headers & libs from this script.

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Perfect, thank you!

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Leaving this here for future masochists to find on Google:

Want to use .NET NativeAOT with this script's Visual Studio environment? Pass in /p:IlcUseEnvironmentalTools=true into dotnet publish.

Hope this helps! I sure wish someone had documented this before... but oh well, atleast others won't suffer as much as I did

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I hit this error, what cert does it complain about?

    return self.do_open(http.client.HTTPSConnection, req,
  File "C:\Users\user\AppData\Local\Programs\Python\Python312\Lib\urllib\", line 1347, in do_open
    raise URLError(err)
urllib.error.URLError: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: certificate has expired (_ssl.c:1000)>

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Script is connecting to Microsoft server to download MSVC. Expired certificate may be result of incorrect date on your computer - check that you have correct date set. Another reason could be bad 3rd party proxy / firewall / network monitoring or security software which is intercepting all https requests.

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@mmozeiko great advice!
so I opened up the certmgr.msc util and went one by one over all the cert hives and just deleted those that are older then 2024!
it did the trick and I was able to successfully run the script!

proofs -

c:\Prg\>python --show-versions
MSVC versions: 14.29 14.30 14.31 14.32 14.33 14.34 14.35 14.36 14.37 14.38 14.39
Windows SDK versions: 18362 19041 20348 22000 22621

btw, what is the goal of adding this into latest script?

  # executable that is collecting & sending telemetry every time cl/link runs
  (OUTPUT / "VC/Tools/MSVC" / msvcv / f"bin/Host{arch}/{arch}/vctip.exe").unlink(missing_ok=True)

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mmozeiko commented Mar 1, 2024

It deletes vctip.exe ("VC++ Technology Improvement Program") which is runs every time you run cl/link and sends telemetry to Microsoft servers. Compiler & linker still works fine without this file. I don't want compiler making network requests every time I compile something.

You can also opt out of MSVC telemetry by editing registry: But it requires changing HKLM keys, so admin rights required, which I don't want for this python script.

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roy4801 commented Mar 7, 2024

To resolve the SSL error ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: certificate has expired (_ssl.c:1000)
You can add these two lines at the beginning of the

import ssl
ssl._create_default_https_context = ssl._create_unverified_context

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mmozeiko commented Mar 7, 2024

That is a bad way to solve this problem. Do not ever do that. It disables TLS verification, so you won't know if things you connect & download are valid and not intercepted/mangled with. Fix your computer time & apply OS updates instead.

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MagicalDrizzle commented Mar 12, 2024

hi! it seems it's not possible to download hostx64-86 cross toolchain? the bin directory barely have any files afterward.
I tried another tool and the result was the sazme.
it seems this is an issue on microsoft's side?

also, running the script with python 3.12 results in NameError: name 'exit' is not defined
the solution seems to be replacing exit(0) with sys.exit(0).

feature request: is it possible to add the ability to specify the folder where the toolchain is located? at the moment it seems to be hardcoded to msvc.

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mmozeiko commented Mar 12, 2024

There's no issue on MS side. I just never really tested other hosts/targets than x64. I've fixed the script so it now works for x64 host & x86 target. arm/arm64 may still be not properly done, have not tested it.

Not sure why you see error with exit - it is perfectly valid to call, even in Python 3.12:
Only issue I could see is that your Python installation is done in a strange way that does not have default site module.

You can just rename msvc folder after script runs. It's not like this code keeps track of this folder and keeps it up to date or tracks what is installed. This tool is not supposed to be fancy installer. Just a quick "run once and forget" kind of tool.

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