diff --git a/.travis.yml b/.travis.yml
index 3140cb88d2..c301f3d89e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,7 +8,7 @@ before_script:
   - cp -f hudson/connexion.inc config/
   - cp -f hudson/_GV.php config/
   - curl -s http://getcomposer.org/installer | php
-  - php composer.phar install --dev
+  - php composer.phar install --dev --prefer-source
   - sudo apt-get install -y -qq xpdf ffmpeg libavcodec-extra-53 openoffice.org-writer unoconv ghostscript gsfonts dcraw ufraw graphicsmagick libgraphicsmagick1-dev libfreetype6-dev libjpeg-dev libgif-dev libtiff-dev libdjvulibre-dev libwmf-dev libmagickcore-dev libmagickwand-dev libpng-dev gettext zlib1g-dev build-essential libfaac-dev libmp3lame0 libx264-dev libvpx-dev libtheora-dev libvorbis-dev gpac
   - sudo apt-get clean
   - wget http://sphinxsearch.com/files/sphinx-2.0.6-release.tar.gz