diff --git a/chrome/content/scaffold/scaffold.js b/chrome/content/scaffold/scaffold.js
index e1000e92c9..4a0e039a01 100644
--- a/chrome/content/scaffold/scaffold.js
+++ b/chrome/content/scaffold/scaffold.js
@@ -30,7 +30,7 @@ var { RemoteTranslate } = ChromeUtils.import("chrome://zotero/content/RemoteTran
 var { ContentDOMReference } = ChromeUtils.import("resource://gre/modules/ContentDOMReference.jsm");
 
 var { Zotero } = ChromeUtils.importESModule("chrome://zotero/content/zotero.mjs");
-import FilePicker from 'zotero/modules/filePicker';
+var { FilePicker } = ChromeUtils.importESModule('chrome://zotero/content/modules/filePicker.mjs');
 
 // Fix JSON stringify 2028/2029 "bug"
 // Borrowed from http://stackoverflow.com/questions/16686687/json-stringify-and-u2028-u2029-check
diff --git a/chrome/content/zotero/fileInterface.js b/chrome/content/zotero/fileInterface.js
index 9afe469e9b..768ec2b23e 100644
--- a/chrome/content/zotero/fileInterface.js
+++ b/chrome/content/zotero/fileInterface.js
@@ -23,9 +23,8 @@
     ***** END LICENSE BLOCK *****
 */
 
-Components.utils.import("resource://gre/modules/osfile.jsm");
 Components.utils.import("resource://gre/modules/Services.jsm");
-import FilePicker from 'zotero/modules/filePicker';
+var { FilePicker } = ChromeUtils.importESModule('chrome://zotero/content/modules/filePicker.mjs');
 import { ImportCitaviAnnotatons } from 'zotero/import/citavi';
 
 /****Zotero_File_Exporter****
diff --git a/chrome/content/zotero/import/importWizard.js b/chrome/content/zotero/import/importWizard.js
index dbf7c2d9cd..40aa38191c 100644
--- a/chrome/content/zotero/import/importWizard.js
+++ b/chrome/content/zotero/import/importWizard.js
@@ -25,7 +25,7 @@
 /* eslint camelcase: ["error", {allow: ["Zotero_File_Interface", "Zotero_Import_Wizard"]} ] */
 /* global Zotero_File_Interface: false, mendeleyAPIUtils: false */
 
-import FilePicker from 'zotero/filePicker';
+var { FilePicker } = ChromeUtils.importESModule('chrome://zotero/content/modules/filePicker.mjs');
 import React from 'react';
 import ReactDOM from 'react-dom';
 import ProgressQueueTable from 'components/progressQueueTable';
diff --git a/chrome/content/zotero/modules/filePicker.js b/chrome/content/zotero/modules/filePicker.mjs
similarity index 96%
rename from chrome/content/zotero/modules/filePicker.js
rename to chrome/content/zotero/modules/filePicker.mjs
index 3d45d41675..c6c5b1be52 100644
--- a/chrome/content/zotero/modules/filePicker.js
+++ b/chrome/content/zotero/modules/filePicker.mjs
@@ -23,8 +23,11 @@
     ***** END LICENSE BLOCK *****
 */
 
-import { Cc, Ci, Cu } from 'chrome';
-Cu.import("resource://gre/modules/osfile.jsm");
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+	FileUtils: "resource://gre/modules/FileUtils.sys.mjs",
+});
 
 /**
  * Interface to the system filepicker.
@@ -34,7 +37,7 @@ Cu.import("resource://gre/modules/osfile.jsm");
  *
  * @class
  */
-class FilePicker {
+export class FilePicker {
 	constructor() {
 		this._fp = Cc["@mozilla.org/filepicker;1"].createInstance(Ci.nsIFilePicker);
 	}
@@ -76,7 +79,7 @@ class FilePicker {
 	 * @return {Promise<Integer>} One of the return constants
 	 */
 	async show() {
-		return new Zotero.Promise(function (resolve) {
+		return new Promise(function (resolve) {
 			this._fp.open(returnConstant => resolve(returnConstant));
 		}.bind(this));
 	};
@@ -164,7 +167,7 @@ FilePicker.prototype.filterVideo = 0x200;
 		set: function (val) {
 			if (prop == 'displayDirectory') {
 				// Convert to nsIFile
-				val = Zotero.File.pathToFile(val);
+				val = new lazy.FileUtils.File(val);
 			}
 			this._fp[prop] = val;
 		},
@@ -222,5 +225,3 @@ FilePicker.prototype.filterVideo = 0x200;
 });
 
 Object.freeze(FilePicker.prototype);
-
-export default FilePicker;
\ No newline at end of file
diff --git a/chrome/content/zotero/preferences/preferences_advanced.js b/chrome/content/zotero/preferences/preferences_advanced.js
index 0d8ff40569..34c3b39a37 100644
--- a/chrome/content/zotero/preferences/preferences_advanced.js
+++ b/chrome/content/zotero/preferences/preferences_advanced.js
@@ -24,7 +24,7 @@
 */
 
 Components.utils.import("resource://gre/modules/Services.jsm");
-import FilePicker from 'zotero/modules/filePicker';
+var { FilePicker } = ChromeUtils.importESModule('chrome://zotero/content/modules/filePicker.mjs');
 
 Zotero_Preferences.Advanced = {	
 	init: function () {
diff --git a/chrome/content/zotero/preferences/preferences_cite.jsx b/chrome/content/zotero/preferences/preferences_cite.jsx
index 8281421b8e..a7fd261c3b 100644
--- a/chrome/content/zotero/preferences/preferences_cite.jsx
+++ b/chrome/content/zotero/preferences/preferences_cite.jsx
@@ -25,7 +25,7 @@
 
 "use strict";
 
-import FilePicker from 'zotero/modules/filePicker';
+var { FilePicker } = ChromeUtils.importESModule('chrome://zotero/content/modules/filePicker.mjs');
 
 var React = require('react');
 var ReactDOM = require('react-dom');
diff --git a/chrome/content/zotero/preferences/preferences_general.js b/chrome/content/zotero/preferences/preferences_general.js
index f3c221ea1e..63c13a68e4 100644
--- a/chrome/content/zotero/preferences/preferences_general.js
+++ b/chrome/content/zotero/preferences/preferences_general.js
@@ -27,7 +27,7 @@
 
 Components.utils.import("resource://gre/modules/Services.jsm");
 Components.utils.import("resource://gre/modules/osfile.jsm");
-import FilePicker from 'zotero/modules/filePicker';
+var { FilePicker } = ChromeUtils.importESModule('chrome://zotero/content/modules/filePicker.mjs');
 
 Zotero_Preferences.General = {
 	_openURLResolvers: null,
diff --git a/chrome/content/zotero/rtfScan.js b/chrome/content/zotero/rtfScan.js
index bf3174c029..5ca49898e3 100644
--- a/chrome/content/zotero/rtfScan.js
+++ b/chrome/content/zotero/rtfScan.js
@@ -1,7 +1,7 @@
 import React from 'react';
 import ReactDOM from 'react-dom';
 
-import FilePicker from 'zotero/modules/filePicker';
+var { FilePicker } = ChromeUtils.importESModule('chrome://zotero/content/modules/filePicker.mjs');
 import VirtualizedTable from 'components/virtualized-table';
 import { getCSSIcon } from 'components/icons';
 
diff --git a/chrome/content/zotero/tools/build_typeSchemaData.js b/chrome/content/zotero/tools/build_typeSchemaData.js
index 218a5fbcd8..86f1ce0fbd 100644
--- a/chrome/content/zotero/tools/build_typeSchemaData.js
+++ b/chrome/content/zotero/tools/build_typeSchemaData.js
@@ -1,4 +1,4 @@
-import FilePicker from 'zotero/modules/filePicker';
+var { FilePicker } = ChromeUtils.importESModule('chrome://zotero/content/modules/filePicker.mjs');
 
 (async function () {
     // Create schema
diff --git a/chrome/content/zotero/tools/csledit.js b/chrome/content/zotero/tools/csledit.js
index 30bf09e0ea..43f46640ca 100644
--- a/chrome/content/zotero/tools/csledit.js
+++ b/chrome/content/zotero/tools/csledit.js
@@ -23,7 +23,7 @@
     ***** END LICENSE BLOCK *****
 */
 
-import FilePicker from 'zotero/modules/filePicker';
+var { FilePicker } = ChromeUtils.importESModule('chrome://zotero/content/modules/filePicker.mjs');
 
 var Zotero_CSL_Editor = new function () {
 	let monaco, editor;
diff --git a/chrome/content/zotero/xpcom/dataDirectory.js b/chrome/content/zotero/xpcom/dataDirectory.js
index 3fb16b1b22..e5c8f6cc5b 100644
--- a/chrome/content/zotero/xpcom/dataDirectory.js
+++ b/chrome/content/zotero/xpcom/dataDirectory.js
@@ -25,7 +25,7 @@
 
 "use strict";
 
-import FilePicker from 'zotero/modules/filePicker';
+var { FilePicker } = ChromeUtils.importESModule('chrome://zotero/content/modules/filePicker.mjs');
 
 Zotero.DataDirectory = {
 	MIGRATION_MARKER: 'migrate-dir',
diff --git a/chrome/content/zotero/xpcom/editorInstance.js b/chrome/content/zotero/xpcom/editorInstance.js
index 266992d05d..566d54cf12 100644
--- a/chrome/content/zotero/xpcom/editorInstance.js
+++ b/chrome/content/zotero/xpcom/editorInstance.js
@@ -25,7 +25,7 @@
 
 Components.utils.import("resource://gre/modules/InlineSpellChecker.jsm");
 
-import FilePicker from 'zotero/modules/filePicker';
+var { FilePicker } = ChromeUtils.importESModule('chrome://zotero/content/modules/filePicker.mjs');
 
 // Note: TinyMCE is automatically doing some meaningless corrections to
 // note-editor produced HTML. Which might result to more
diff --git a/chrome/content/zotero/xpcom/reader.js b/chrome/content/zotero/xpcom/reader.js
index 7a806a61e4..97fabed71f 100644
--- a/chrome/content/zotero/xpcom/reader.js
+++ b/chrome/content/zotero/xpcom/reader.js
@@ -23,7 +23,7 @@
     ***** END LICENSE BLOCK *****
 */
 
-import FilePicker from 'zotero/modules/filePicker';
+var { FilePicker } = ChromeUtils.importESModule('chrome://zotero/content/modules/filePicker.mjs');
 
 const { BlockingObserver } = ChromeUtils.import("chrome://zotero/content/BlockingObserver.jsm");
 
diff --git a/chrome/content/zotero/zoteroPane.js b/chrome/content/zotero/zoteroPane.js
index e63b52ea51..619f5c6b77 100644
--- a/chrome/content/zotero/zoteroPane.js
+++ b/chrome/content/zotero/zoteroPane.js
@@ -23,7 +23,7 @@
     ***** END LICENSE BLOCK *****
 */
 
-import FilePicker from 'zotero/modules/filePicker';
+var { FilePicker } = ChromeUtils.importESModule('chrome://zotero/content/modules/filePicker.mjs');
 
 /*
  * This object contains the various functions for the interface
diff --git a/resource/require.js b/resource/require.js
index 8a962d4ad4..12ce7b5638 100644
--- a/resource/require.js
+++ b/resource/require.js
@@ -104,9 +104,6 @@ var require = (function() {
 			'containers/': 'chrome://zotero/content/containers/',
 			'components/': 'chrome://zotero/content/components/',
 			'zotero/': 'chrome://zotero/content/',
-			// TEMP until plugins updated
-			// TODO: Possible to show a deprecation warning?
-			'zotero/filePicker': 'chrome://zotero/content/modules/filePicker',
 		},
 		globals
 	});