--- a/browser/base/content/newtab/sites.js
+++ b/browser/base/content/newtab/sites.js
@@ -290,17 +290,23 @@ Site.prototype = {
   },
 
   /**
    * Speculatively opens a connection to the current site.
    */
   _speculativeConnect: function Site_speculativeConnect() {
     let sc = Services.io.QueryInterface(Ci.nsISpeculativeConnect);
     let uri = Services.io.newURI(this.url, null, null);
-    sc.speculativeConnect(uri, null);
+    try {
+      // This can throw for certain internal URLs, when they wind up in
+      // about:newtab. Be sure not to propagate the error.
+      sc.speculativeConnect(uri, null);
+    } catch (e) {
+      Cu.reportError(e);
+    }
   },
 
   /**
    * Record interaction with site using telemetry.
    */
   _recordSiteClicked: function Site_recordSiteClicked(aIndex) {
     if (Services.prefs.prefHasUserValue("browser.newtabpage.rows") ||
         Services.prefs.prefHasUserValue("browser.newtabpage.columns") ||