diff --git a/chrome/content/zotero/locateMenu.js b/chrome/content/zotero/locateMenu.js
index 35aa69fb69..d7d8b68fb4 100644
--- a/chrome/content/zotero/locateMenu.js
+++ b/chrome/content/zotero/locateMenu.js
@@ -29,7 +29,7 @@ var { XPCOMUtils } = ChromeUtils.importESModule("resource://gre/modules/XPCOMUti
  * This object contains the various functions for the interface
  */
 var Zotero_LocateMenu = new function () {
-	XPCOMUtils.defineLazyServiceGetter(this, "ios", "@mozilla.org/network/io-service;1", "nsIIOService");
+	XPCOMUtils.defineLazyServiceGetter(this, "ios", "@mozilla.org/network/io-service;1", Ci.nsIIOService);
 	
   	/**
   	 * Clear and build the locate menu
diff --git a/chrome/content/zotero/xpcom/plugins.js b/chrome/content/zotero/xpcom/plugins.js
index 340f747c85..8369a93c77 100644
--- a/chrome/content/zotero/xpcom/plugins.js
+++ b/chrome/content/zotero/xpcom/plugins.js
@@ -34,7 +34,7 @@ Zotero.Plugins = new function () {
 	XPCOMUtils.defineLazyServiceGetters(lazy, {
 		aomStartup: [
 			"@mozilla.org/addons/addon-manager-startup;1",
-			"amIAddonManagerStartup",
+			Ci.amIAddonManagerStartup,
 		],
 	});
 	var scopes = new Map();
diff --git a/resource/loader.sys.mjs b/resource/loader.sys.mjs
index c85821a36c..2ff9f627ff 100644
--- a/resource/loader.sys.mjs
+++ b/resource/loader.sys.mjs
@@ -17,7 +17,7 @@ XPCOMUtils.defineLazyServiceGetter(
     lazy,
     "resProto",
     "@mozilla.org/network/protocol;1?name=resource",
-    "nsIResProtocolHandler"
+    Ci.nsIResProtocolHandler
 );
 
 ChromeUtils.defineESModuleGetters(