diff --git a/.travis.yml b/.travis.yml
index b9af84bff..0b6034db2 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -225,6 +225,7 @@ matrix:
         homebrew:
           packages:
             - ccache
+          update: true
       env:
         - MATRIX_EVAL="brew install python2 || brew link --overwrite python@2"  # deficient python2 in travis's xcode8.3 (no ssl)
         - ARCHFLAGS="-std=c++11"
@@ -281,6 +282,7 @@ matrix:
         homebrew:
           packages:
             - ccache
+          update: true
       env:
         - MATRIX_EVAL="brew update; brew tap sashkab/python; brew install sashkab/python/python36; brew link --force --overwrite python36; shopt -s expand_aliases; alias python='/usr/local/opt/python36/bin/python3.6'; alias pip='/usr/local/opt/python36/bin/pip3.6';"
         - ARCHFLAGS="-std=c++11"
@@ -298,6 +300,7 @@ matrix:
         homebrew:
           packages:
             - ccache
+          update: true
       env:
         - MATRIX_EVAL="brew update; brew tap sashkab/python; brew install sashkab/python/python35; brew link --force --overwrite python35; shopt -s expand_aliases; alias python='/usr/local/opt/python35/bin/python3.5'; alias pip='/usr/local/opt/python35/bin/pip3.5';"
         - ARCHFLAGS="-std=c++11"