diff --git a/.dockerignore b/.dockerignore
index f59ec20..319b932 100644
--- a/.dockerignore
+++ b/.dockerignore
@@ -1 +1,2 @@
-*
\ No newline at end of file
+*
+!packages/
diff --git a/Dockerfile b/Dockerfile
index 0072d9e..c65bf9c 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,22 +1,32 @@
 FROM python:3.13-slim-bullseye
 
-USER root
-
-ARG INSTALL_GIT=false
-RUN if [ "$INSTALL_GIT" = "true" ]; then \
-    apt-get update && apt-get install -y git && rm -rf /var/lib/apt/lists/*; \
-    fi
+ENV DEBIAN_FRONTEND=noninteractive
+ENV EXIFTOOL_PATH=/usr/bin/exiftool
+ENV FFMPEG_PATH=/usr/bin/ffmpeg
 
 # Runtime dependency
 RUN apt-get update && apt-get install -y --no-install-recommends \
     ffmpeg \
-    && rm -rf /var/lib/apt/lists/*
+    exiftool
 
-RUN pip install markitdown
+ARG INSTALL_GIT=false
+RUN if [ "$INSTALL_GIT" = "true" ]; then \
+    apt-get install -y --no-install-recommends \
+    git; \
+    fi
+
+# Cleanup
+RUN rm -rf /var/lib/apt/lists/*
+
+WORKDIR /app
+COPY . /app
+RUN pip --no-cache-dir install \
+    /app/packages/markitdown[all] \
+    /app/packages/markitdown-sample-plugin
 
 # Default USERID and GROUPID
-ARG USERID=10000
-ARG GROUPID=10000
+ARG USERID=nobody
+ARG GROUPID=nogroup
 
 USER $USERID:$GROUPID
 
diff --git a/packages/markitdown/src/markitdown/_markitdown.py b/packages/markitdown/src/markitdown/_markitdown.py
index f32b236..04015d7 100644
--- a/packages/markitdown/src/markitdown/_markitdown.py
+++ b/packages/markitdown/src/markitdown/_markitdown.py
@@ -327,6 +327,17 @@ class MarkItDown:
         elif base_guess.extension is not None:
             placeholder_filename = "placeholder" + base_guess.extension
 
+        # Check if we have a seekable stream. If not, load the entire stream into memory.
+        if not stream.seekable():
+            buffer = io.BytesIO()
+            while True:
+                chunk = stream.read(4096)
+                if not chunk:
+                    break
+                buffer.write(chunk)
+            buffer.seek(0)
+            stream = buffer
+
         # Add guesses based on stream content
         for guess in _guess_stream_info_from_stream(
             file_stream=stream, filename_hint=placeholder_filename
diff --git a/packages/markitdown/src/markitdown/converters/_outlook_msg_converter.py b/packages/markitdown/src/markitdown/converters/_outlook_msg_converter.py
index 8a61b0c..8e20dc5 100644
--- a/packages/markitdown/src/markitdown/converters/_outlook_msg_converter.py
+++ b/packages/markitdown/src/markitdown/converters/_outlook_msg_converter.py
@@ -7,6 +7,7 @@ from .._exceptions import MissingDependencyException, MISSING_DEPENDENCY_MESSAGE
 # Try loading optional (but in this case, required) dependencies
 # Save reporting of any exceptions for later
 _dependency_exc_info = None
+olefile = None
 try:
     import olefile
 except ImportError:
@@ -48,7 +49,7 @@ class OutlookMsgConverter(DocumentConverter):
         # Brute force, check if we have an OLE file
         cur_pos = file_stream.tell()
         try:
-            if not olefile.isOleFile(file_stream):
+            if olefile and not olefile.isOleFile(file_stream):
                 return False
         finally:
             file_stream.seek(cur_pos)