diff --git a/Dockerfile b/Dockerfile
index 8f04555..e757015 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -6,9 +6,9 @@ ENV TZ=America/New_York \
     MAILBAGIT_LOG_LEVEL=debug\
     IN_CONTAINER=true
 
-RUN mkdir /mailbagit
-WORKDIR /mailbagit
-ADD . /mailbagit/
+#RUN mkdir /mailbagit
+#WORKDIR /mailbagit
+#ADD . /mailbagit/
 
 # manually add to $PYTHONPATH because https://github.com/python/importlib_metadata/issues/364
 ENV PYTHONPATH=/mailbagit
@@ -32,5 +32,3 @@ RUN apt-get install -y /tmp/google-chrome-stable_current_amd64.deb
 RUN curl -L -o /tmp/wkhtmltox_0.12.6-1.buster_amd64.deb \ 
         https://github.com/wkhtmltopdf/packaging/releases/download/0.12.6-1/wkhtmltox_0.12.6-1.buster_amd64.deb
 RUN dpkg -i /tmp/wkhtmltox_0.12.6-1.buster_amd64.deb
-
-RUN pip install -e .[pst]
diff --git a/docker-compose-dev.yml b/docker-compose-dev.yml
new file mode 100644
index 0000000..3447884
--- /dev/null
+++ b/docker-compose-dev.yml
@@ -0,0 +1,13 @@
+version: '3.1'
+
+services:
+  mailbagit:
+    image: ualbanyarchives/mailbagit:dev
+    volumes:
+      - '../sampleData:/data'
+      - '.:/mailbagit'
+    tty: true
+    stdin_open: true
+    restart: always
+    working_dir: /mailbagit
+    entrypoint: /bin/bash
\ No newline at end of file
diff --git a/docs/installing_mailbagit/docker.md b/docs/installing_mailbagit/docker.md
index 2f5be6a..f6676ce 100755
--- a/docs/installing_mailbagit/docker.md
+++ b/docs/installing_mailbagit/docker.md
@@ -35,7 +35,7 @@ docker compose run mailbag
 
 ## Run with bind mount.
 
-You can also use a bind mount to give the container and `mailbagit` access to the files you want to process.
+You can also use a bind mount to give the container and `mailbagit` access to another directory.
 
 Mailbagit will have access to the directory listed in the `source=` argument, which will be accessible in the container using the `/data` path.
 
@@ -79,11 +79,12 @@ Remember to stop the container when you're done!
 
 ## Development Docker image
 
-There is also a development image available:
+There is also a development image available. This contains an consistent environment for mailbagit, but allows you to work directly with local code. Mounts a directory with test email data at `../sampleData` to `/data`.
 
 ```
 docker pull ualbanyarchives/mailbagit:dev
-docker run -it ualbanyarchives/mailbagit:dev
+docker compose -f docker-compose-dev.yml run mailbagit
+pip install -e .[pst]
 ```
 
 ### Other helpful docker commands
diff --git a/mailbagit/__init__.py b/mailbagit/__init__.py
index ad9ee2b..f993d8b 100644
--- a/mailbagit/__init__.py
+++ b/mailbagit/__init__.py
@@ -1,7 +1,7 @@
 # __init__.py
 
 # Version of the mailbagit package
-__version__ = "0.5.0"
+__version__ = "0.5.1"
 
 import os
 from pathlib import Path
diff --git a/mailbagit/formats/mbox.py b/mailbagit/formats/mbox.py
index fc8b304..e44f409 100644
--- a/mailbagit/formats/mbox.py
+++ b/mailbagit/formats/mbox.py
@@ -59,7 +59,8 @@ def messages(self, iteration_only=False):
                     fileRoot = root + os.sep
                     # don't count the newly-created mailbag
                     if not fileRoot.startswith(mailbag_path):
-                        if file.lower().endswith("." + self.format_name):
+                        # Mac Mail export file is "mbox" without an extension, so this checks that
+                        if file.lower().endswith("." + self.format_name) or file.lower().strip() == "mbox":
                             fileList.append(os.path.join(root, file))
                         elif self.companion_files:
                             companion_files.append(os.path.join(root, file))
diff --git a/setup.py b/setup.py
index d00cd06..8d5791a 100755
--- a/setup.py
+++ b/setup.py
@@ -6,7 +6,7 @@
 
 setuptools.setup(
     name="mailbagit",
-    version="0.5.0",
+    version="0.5.1",
     author="Gregory Wiedeman",
     author_email="gwiedeman@albany.edu",
     description="A tool for preserving email with multiple masters.",