diff --git a/CHANGELOG.md b/CHANGELOG.md
index e4c6267..4722677 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@ Note: Breaking changes between versions are indicated by "💥".
 
 ## Unreleased
 
+- [Bugfix] Fix user ID checking under Windows.
 - [Bugfix] Fix template rendering for Windows users.
 - [Improvement] Switch to `bcrypt` for htpasswd password generation, for better portability on Windows.
 - [Improvement] In the openedx production docker image, add some jitter to the gunicorn worker restart process to prevent all workers from restarting at the same time.
diff --git a/tutor/commands/cli.py b/tutor/commands/cli.py
index 1935112..e5948c0 100755
--- a/tutor/commands/cli.py
+++ b/tutor/commands/cli.py
@@ -1,5 +1,4 @@
 #! /usr/bin/env python3
-import os
 import sys
 
 import appdirs
@@ -19,6 +18,7 @@ from .webui import webui
 from ..__about__ import __version__
 from .. import exceptions
 from .. import fmt
+from .. import utils
 
 
 def main():
@@ -54,9 +54,11 @@ def main():
 )
 @click.pass_context
 def cli(context, root):
-    if os.getuid() == 0:
+    if utils.get_user_id() == 0:
         fmt.echo_alert(
-            "You are running Tutor as root. This is strongly not recommended. If you are doing this in order to access the Docker daemon, you should instead add your user to the 'docker' group. (see https://docs.docker.com/install/linux/linux-postinstall/#manage-docker-as-a-non-root-user)"
+            "You are running Tutor as root. This is strongly not recommended. If you are doing this in order to access"
+            " the Docker daemon, you should instead add your user to the 'docker' group. (see https://docs.docker.com"
+            "/install/linux/linux-postinstall/#manage-docker-as-a-non-root-user)"
         )
     context.obj = Context(root)
 
diff --git a/tutor/commands/dev.py b/tutor/commands/dev.py
index 4a436e9..825f8c4 100644
--- a/tutor/commands/dev.py
+++ b/tutor/commands/dev.py
@@ -9,6 +9,7 @@ from .. import env as tutor_env
 from .. import fmt
 from .. import utils
 
+
 # pylint: disable=too-few-public-methods
 class DevContext(Context):
     @staticmethod
diff --git a/tutor/commands/images.py b/tutor/commands/images.py
index 6d03efc..18d99cd 100644
--- a/tutor/commands/images.py
+++ b/tutor/commands/images.py
@@ -1,11 +1,10 @@
-import subprocess
-
 import click
 
 from .. import config as tutor_config
 from .. import env as tutor_env
 from .. import images
 from .. import plugins
+from .. import utils
 
 BASE_IMAGE_NAMES = ["openedx", "forum", "android"]
 DEV_IMAGE_NAMES = ["openedx-dev"]
@@ -93,8 +92,7 @@ def build_image(root, config, image, *args):
         )
 
     # Build dev images with user id argument
-    user_id = subprocess.check_output(["id", "-u"]).strip().decode()
-    dev_build_arg = ["--build-arg", "USERID={}".format(user_id)]
+    dev_build_arg = ["--build-arg", "USERID={}".format(utils.get_user_id())]
     for img, tag in iter_images(config, image, DEV_IMAGE_NAMES):
         images.build(tutor_env.pathjoin(root, "build", img), tag, *dev_build_arg, *args)
 
diff --git a/tutor/utils.py b/tutor/utils.py
index a254700..c417121 100644
--- a/tutor/utils.py
+++ b/tutor/utils.py
@@ -126,6 +126,15 @@ def walk_files(path):
             yield os.path.join(dirpath, filename)
 
 
+def get_user_id():
+    """
+    Portable way to get user ID. Note: I have no idea if it actually works on windows...
+    """
+    if sys.platform == "windows":
+        return int(check_output("id", "-u").decode())
+    return os.getuid()
+
+
 def docker_run(*command):
     args = ["run", "--rm"]
     if is_a_tty():
@@ -190,6 +199,5 @@ def check_output(*command):
     click.echo(fmt.command(" ".join(command)))
     try:
         return subprocess.check_output(command)
-    except:
+    finally:
         fmt.echo_error("Command failed: {}".format(" ".join(command)))
-        raise