diff --git a/test/runtests.sh b/test/runtests.sh
index 8d003db806..c23c3d8eb2 100755
--- a/test/runtests.sh
+++ b/test/runtests.sh
@@ -169,6 +169,7 @@ user_pref("extensions.zotero.reportTranslationFailure", false);
 user_pref("extensions.zotero.httpServer.enabled", true);
 user_pref("extensions.zotero.backup.numBackups", 0);
 user_pref("extensions.zotero.sync.autoSync", false);
+user_pref("extensions.legacy.enabled", true);
 user_pref("xpinstall.signatures.required", false);
 user_pref("xpinstall.whitelist.required", false);
 user_pref("datareporting.healthreport.uploadEnabled", false);