--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -5128,17 +5128,18 @@ pref("browser.safebrowsing.provider.goog
 pref("browser.safebrowsing.provider.google.updateURL", "https://safebrowsing.google.com/safebrowsing/downloads?client=SAFEBROWSING_ID&appver=%MAJOR_VERSION%&pver=2.2&key=%GOOGLE_API_KEY%");
 pref("browser.safebrowsing.provider.google.gethashURL", "https://safebrowsing.google.com/safebrowsing/gethash?client=SAFEBROWSING_ID&appver=%MAJOR_VERSION%&pver=2.2");
 pref("browser.safebrowsing.provider.google.reportURL", "https://safebrowsing.google.com/safebrowsing/diagnostic?client=%NAME%&hl=%LOCALE%&site=");
 
 // Prefs for v4.
 pref("browser.safebrowsing.provider.google4.pver", "4");
 pref("browser.safebrowsing.provider.google4.lists", "goog-phish-proto,googpub-phish-proto,goog-malware-proto,goog-unwanted-proto");
 pref("browser.safebrowsing.provider.google4.updateURL", "https://safebrowsing.googleapis.com/v4/threatListUpdates:fetch?$ct=application/x-protobuf&key=%GOOGLE_API_KEY%");
-pref("browser.safebrowsing.provider.google4.gethashURL", "https://safebrowsing.googleapis.com/v4/fullHashes:find?$ct=application/x-protobuf&key=%GOOGLE_API_KEY%");
+// Leave it empty until we roll out v4 hash completion feature. See Bug 1323856.
+pref("browser.safebrowsing.provider.google4.gethashURL", "");
 pref("browser.safebrowsing.provider.google4.reportURL", "https://safebrowsing.google.com/safebrowsing/diagnostic?client=%NAME%&hl=%LOCALE%&site=");
 
 pref("browser.safebrowsing.reportPhishMistakeURL", "https://%LOCALE%.phish-error.mozilla.com/?hl=%LOCALE%&url=");
 pref("browser.safebrowsing.reportPhishURL", "https://%LOCALE%.phish-report.mozilla.com/?hl=%LOCALE%&url=");
 pref("browser.safebrowsing.reportMalwareMistakeURL", "https://%LOCALE%.malware-error.mozilla.com/?hl=%LOCALE%&url=");
 
 // The table and global pref for blocking plugin content
 pref("browser.safebrowsing.blockedURIs.enabled", true);