diff --git a/zsh/zshrc b/zsh/zshrc
index 5db9651..74eefbf 100755
--- a/zsh/zshrc
+++ b/zsh/zshrc
@@ -13,9 +13,12 @@ if which narwhal-jsc >/dev/null 2>&1; then
     export NARWHAL_ENGINE=jsc
 fi
 
-# for riak and possibly building javascriptcore
 if mac; then
+    # for riak and possibly building javascriptcore
     export COMMAND_MODE=unix2003
+
+    # Don't pollute tar archives with ._ files (Apple double files)
+    export COPYFILE_DISABLE=true
 fi
 
 export LC_ALL="en_CA.UTF-8"