diff --git a/copyparty/__version__.py b/copyparty/__version__.py
index 0181d2ca..9264f185 100644
--- a/copyparty/__version__.py
+++ b/copyparty/__version__.py
@@ -1,6 +1,6 @@
 # coding: utf-8
 
-VERSION = (0, 13, 8)
+VERSION = (0, 13, 9)
 CODENAME = "future-proof"
 BUILD_DT = (2021, 8, 29)
 
diff --git a/copyparty/web/browser.js b/copyparty/web/browser.js
index 24c97c02..bccb3822 100644
--- a/copyparty/web/browser.js
+++ b/copyparty/web/browser.js
@@ -704,7 +704,7 @@ var pbar = (function () {
 
 		pctx.clearRect(0, 0, pc.w, pc.h);
 
-		if (!mp.au || mp.loading || isNaN(adur = mp.au.duration) || isNaN(apos = mp.au.currentTime))
+		if (!mp.au || mp.loading || isNaN(adur = mp.au.duration) || isNaN(apos = mp.au.currentTime) || apos < 0 || adur < apos)
 			return;  // not-init || unsupp-codec
 
 		var sm = bc.w * 1.0 / adur;