diff --git a/.travis.yml b/.travis.yml
index 7632745..57e6021 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,17 +2,17 @@ language: generic
 os:
 - osx
 - linux
-osx_image: xcode7.3
+osx_image: xcode8.3
 sudo: required
 install:
-- if [ "$TRAVIS_OS_NAME" = "osx" ]; then bash package/prepare_osx.sh; fi
-- if [ "$TRAVIS_OS_NAME" = "linux" ]; then bash package/prepare_linux.sh; fi
+- if [ "$TRAVIS_OS_NAME" = "osx" ]; then package/prepare_osx.sh; fi
+- if [ "$TRAVIS_OS_NAME" = "linux" ]; then package/prepare_linux.sh; fi
 script:
 - if [ "$TRAVIS_OS_NAME" = "osx" ]; then python3 -B -m pytest -vs; fi
 - if [ "$TRAVIS_OS_NAME" = "linux" ]; then xvfb-run -s '-screen 0 640x480x24 +extension GLX' pytest -vs; fi
 before_deploy:
 - export FILENAME=manuskript-$TRAVIS_BRANCH-$TRAVIS_OS_NAME.zip
-- if [ "$TRAVIS_OS_NAME" = "osx" ]; then bash package/build_osx.sh; fi
+- if [ "$TRAVIS_OS_NAME" = "osx" ]; then package/build_osx.sh; fi
 deploy:
   - provider: releases
     api_key:
diff --git a/package/prepare_osx.sh b/package/prepare_osx.sh
index 4c2bf9b..8f937a1 100755
--- a/package/prepare_osx.sh
+++ b/package/prepare_osx.sh
@@ -1,12 +1,21 @@
 #!/bin/bash
-set -ev
+set -ev   # display each line executed along with output
 brew update
-# upgrade to python 3.x
+# Upgrade to python 3.x
 brew upgrade python
 brew install enchant
-brew postinstall python # this installs pip
+brew postinstall python   # this installs pip
 sudo -H pip3 install --upgrade pip setuptools wheel
 pip3 install pyinstaller PyQt5 lxml pyenchant pytest pytest-faulthandler
-brew install qt hunspell
-# fooling PyEnchant as described in the wiki: https://github.com/olivierkes/manuskript/wiki/Package-manuskript-for-OS-X
+brew install hunspell
+# Fooling PyEnchant as described in the wiki.
+#   https://github.com/olivierkes/manuskript/wiki/Package-manuskript-for-OS-X
 sudo touch /usr/local/share/aspell
+#
+# Note that if qt install is terminated by Travis CI then it is likely
+#   building from source instead of pouring from a homebrew bottle.
+#   Fix by choosing lowest osx_image value [1] for xcode that has a
+#   homebrew qt bottle [2].
+#   [1] https://docs.travis-ci.com/user/reference/osx#os-x-version
+#   [2] https://formulae.brew.sh/formula/qt
+brew install qt