diff --git a/test/runtests.sh b/test/runtests.sh
index 0f8f28ef13..99a1478066 100755
--- a/test/runtests.sh
+++ b/test/runtests.sh
@@ -133,6 +133,8 @@ user_pref("browser.tabs.remote.autostart.2", false);
 user_pref("browser.uitour.enabled", false);
 user_pref("browser.shell.checkDefaultBrowser", false);
 user_pref("dom.max_chrome_script_run_time", 0);
+// It would be better to leave this on and handle it in Sinon's FakeXMLHttpRequest
+user_pref("extensions.zotero.sync.server.compressData", false);
 user_pref("extensions.zotero.debug.log", $DEBUG);
 user_pref("extensions.zotero.debug.level", $DEBUG_LEVEL);
 user_pref("extensions.zotero.debug.time", $DEBUG);