diff --git a/pkgs/applications/networking/instant-messengers/slack/default.nix b/pkgs/applications/networking/instant-messengers/slack/default.nix
index ad831eb82a59..f46a293be974 100644
--- a/pkgs/applications/networking/instant-messengers/slack/default.nix
+++ b/pkgs/applications/networking/instant-messengers/slack/default.nix
@@ -158,7 +158,7 @@ let
       mkdir -p $out/Applications
       cp -r ./slack-mnt/Slack.app $out/Applications
       /usr/bin/hdiutil unmount slack-mnt
-      defaults write com.tinyspeck.slackmacgap SlackNoAutoUpdates -bool YES
+      /usr/bin/defaults write com.tinyspeck.slackmacgap SlackNoAutoUpdates -bool YES
     '';
   };
 in if stdenv.isDarwin