diff --git a/chrome/content/zotero/xpcom/zotero.js b/chrome/content/zotero/xpcom/zotero.js
index a2f53f07b1..6125dfcdf9 100644
--- a/chrome/content/zotero/xpcom/zotero.js
+++ b/chrome/content/zotero/xpcom/zotero.js
@@ -1441,6 +1441,8 @@ Services.scriptloader.loadSubScript("resource://zotero/polyfill.js");
 	 * @return	void
 	 */
 	this.showZoteroPaneProgressMeter = function (msg, determinate, icon, modalOnly) {
+		const HTML_NS = "http://www.w3.org/1999/xhtml"
+		
 		// If msg is undefined, keep any existing message. If false/null/"", clear.
 		// The message is also cleared when the meters are hidden.
 		_progressMessage = msg = (msg === undefined ? _progressMessage : msg) || "";
@@ -1475,17 +1477,15 @@ Services.scriptloader.loadSubScript("resource://zotero/polyfill.js");
 			let id = 'zotero-pane-progressmeter';
 			let progressMeter = doc.getElementById(id);
 			if (!progressMeter) {
-				progressMeter = doc.createElement('progressmeter');
+				progressMeter = doc.createElementNS(HTML_NS, 'progress');
 				progressMeter.id = id;
 			}
-			progressMeter.setAttribute('mode', 'undetermined');
 			if (determinate) {
-				progressMeter.mode = 'determined';
-				progressMeter.value = 0;
+				progressMeter.setAttribute('value', 0);
 				progressMeter.max = 1000;
 			}
 			else {
-				progressMeter.mode = 'undetermined';
+				progressMeter.removeAttribute('value');
 			}
 			container.appendChild(progressMeter);
 			
@@ -1515,13 +1515,13 @@ Services.scriptloader.loadSubScript("resource://zotero/polyfill.js");
 		}
 		for (let pm of _progressMeters) {
 			if (percentage !== null) {
-				if (pm.mode == 'undetermined') {
+				if (!pm.hasAttribute('value')) {
 					pm.max = 1000;
-					pm.mode = 'determined';
 				}
-				pm.value = percentage;
-			} else if(pm.mode === 'determined') {
-				pm.mode = 'undetermined';
+				pm.setAttribute('value', percentage);
+			}
+			else if (pm.hasAttribute('value')) {
+				pm.removeAttribute('value');
 			}
 		}
 		_lastPercentage = percentage;