diff --git a/containers/zammad/setup.sh b/containers/zammad/setup.sh
index 21e1715..47160f3 100755
--- a/containers/zammad/setup.sh
+++ b/containers/zammad/setup.sh
@@ -3,7 +3,7 @@ set -e
 
 # install dependencies
 if [ "$1" = 'builder' ]; then
-  PACKAGES="build-essential curl git libimlib2-dev libpq-dev"
+  PACKAGES="build-essential curl git libimlib2-dev libpq-dev shared-mime-info"
 elif [ "$1" = 'runner' ]; then
   PACKAGES="curl libimlib2 libpq5 nginx rsync"
 fi