diff --git a/linux/build/preferences/i2pdbrowser.cfg b/linux/build/preferences/i2pdbrowser.cfg
index 6336c67..19984d5 100644
--- a/linux/build/preferences/i2pdbrowser.cfg
+++ b/linux/build/preferences/i2pdbrowser.cfg
@@ -262,6 +262,7 @@ pref("network.predictor.enabled", false);
 pref("network.predictor.enable-prefetch", false);
 defaultPref("network.prefetch-next", false);
 pref("network.protocol-handler.expose-all", true);
+pref("network.protocol-handler.external.mailto", false);
 defaultPref("network.protocol-handler.external-default", false);
 defaultPref("network.protocol-handler.warn-external-default", true);
 pref("network.http.speculative-parallel-limit", 0);