diff --git a/Dockerfile b/Dockerfile
index bda9e37..91e9bf6 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -20,6 +20,10 @@ RUN useradd -m -u 10001 app
 # Independent of $HOME regardless: keeps the cache path explicit and writable
 # by the app user even if the home directory assumption ever changes.
 ENV UV_CACHE_DIR=/tmp/uv-cache
+# `uv run` must use the venv built by `uv sync` below as it is: re-validating
+# the project would look for vendor/visionsuite (the vision-worker extra), which
+# this image does not carry (issue 39). `uv sync` itself is not affected by it.
+ENV UV_NO_SYNC=1
 
 WORKDIR /app
 
@@ -36,7 +40,7 @@ COPY src/ ./src/
 
 # Uploads directory (mounted as a volume in production).
 RUN mkdir -p /app/uploads/images /app/uploads/pdfs /app/uploads/logos /app/uploads/reports \
-    && chown -R app:app /app
+    && chown -R app:app /app /tmp/uv-cache
 
 USER app
 
diff --git a/Dockerfile.frontend b/Dockerfile.frontend
index 4715cc3..53f6a1b 100644
--- a/Dockerfile.frontend
+++ b/Dockerfile.frontend
@@ -25,6 +25,10 @@ RUN useradd -m -u 10001 app
 # Independent of $HOME regardless: keeps the cache path explicit and writable
 # by the app user even if the home directory assumption ever changes.
 ENV UV_CACHE_DIR=/tmp/uv-cache
+# `uv run` must use the venv built by `uv sync` below as it is: re-validating
+# the project would look for vendor/visionsuite (the vision-worker extra), which
+# this image does not carry (issue 39). `uv sync` itself is not affected by it.
+ENV UV_NO_SYNC=1
 
 WORKDIR /app
 
@@ -41,7 +45,7 @@ COPY --from=tailwind-build /app/flask_app/static/css/tailwind.css ./flask_app/st
 # Compile Flask-Babel translation catalogs.
 WORKDIR /app/flask_app
 RUN uv run --project /app pybabel compile -d translations && \
-    chown -R app:app /app
+    chown -R app:app /app /tmp/uv-cache
 
 USER app
 
diff --git a/Dockerfile.vision b/Dockerfile.vision
index a2c9e84..400c248 100644
--- a/Dockerfile.vision
+++ b/Dockerfile.vision
@@ -43,7 +43,7 @@ RUN test -n "$VISION_ENGINE_VERSION" || { \
     }
 ENV VISION_ENGINE_VERSION=${VISION_ENGINE_VERSION}
 
-RUN chown -R app:app /app
+RUN chown -R app:app /app /tmp/uv-cache
 USER app
 
 EXPOSE 8100