diff --git a/.drone.yml b/.drone.yml
index aeedfb3..929096d 100644
--- a/.drone.yml
+++ b/.drone.yml
@@ -7,7 +7,7 @@ steps:
   image: alpine
   commands:
   - apk add --no-cache python3 py3-lxml py3-setproctitle py3-pip py3-wheel py3-enchant hunspell-en
-  - pip3 install --no-cache-dir .[full] .[dev]
+  - pip3 install --no-cache-dir --ignore-installed .[full] .[dev]
   - isort --check-only --diff .
   - pylint morss --rcfile=.pylintrc --disable=C,R,W --fail-under=8
 
diff --git a/Dockerfile b/Dockerfile
index 6078c0f..e8a5211 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -5,7 +5,7 @@ ADD . /app
 RUN set -ex; \
 	apk add --no-cache --virtual .run-deps python3 py3-lxml py3-setproctitle py3-setuptools; \
 	apk add --no-cache --virtual .build-deps py3-pip py3-wheel; \
-	pip3 install --no-cache-dir /app[full]; \
+	pip3 install --no-cache-dir --ignore-installed /app[full]; \
 	apk del .build-deps
 
 USER 1000:1000