diff --git a/chrome/content/zotero/xpcom/sync.js b/chrome/content/zotero/xpcom/sync.js
index 68365d8e9..162eaefcd 100644
--- a/chrome/content/zotero/xpcom/sync.js
+++ b/chrome/content/zotero/xpcom/sync.js
@@ -846,9 +846,6 @@ Zotero.Sync.Server = new function () {
 		if (!username) {
 			_error("Username not set in Zotero.Sync.Server.login()");
 		}
-		else if (!username.match(/^[\w\d\. \-\_]+$/)) {
-			_error("Invalid username '" + username + "' in Zotero.Sync.Server.login()");
-		}
 		
 		username = encodeURIComponent(Zotero.Sync.Server.username);
 		var password = encodeURIComponent(Zotero.Sync.Server.password);