diff --git a/test/runtests.sh b/test/runtests.sh
index 3eab0a98f..ea19f4bf1 100755
--- a/test/runtests.sh
+++ b/test/runtests.sh
@@ -107,6 +107,7 @@ user_pref("extensions.zotero.firstRun2", false);
 user_pref("extensions.zotero.reportTranslationFailure", false);
 user_pref("extensions.zotero.httpServer.enabled", true);
 user_pref("extensions.zotero.backup.numBackups", 0);
+user_pref("xpinstall.signatures.required", false);
 EOF
 
 # -v flag on Windows makes Firefox process hang