diff --git a/js/client-mainmenu.js b/js/client-mainmenu.js
index be147f8ad..2eadae5d0 100644
--- a/js/client-mainmenu.js
+++ b/js/client-mainmenu.js
@@ -342,9 +342,14 @@
 			var $pmWindow = $(target).closest('.pm-window');
 			var userid = $pmWindow.data('userid');
 
+			var format = $pmWindow.find('button[name=format]').val();
 			var teamIndex = $pmWindow.find('button[name=team]').val();
 			var team = null;
 			if (app.user.teams[teamIndex]) team = app.user.teams[teamIndex].team;
+			if (!window.BattleFormats[format].team && !team) {
+				app.addPopupMessage("You need to go into the Teambuilder and build a team for this format.");
+				return;
+			}
 
 			$(target).closest('.challenge').remove();
 			app.send('/utm '+(team?$.toJSON(team):'null'));
@@ -360,11 +365,15 @@
 			var $pmWindow = $(target).closest('.pm-window');
 			var userid = $pmWindow.data('userid');
 			var name = $pmWindow.data('name');
-			var format = $pmWindow.find('button[name=format]').val();
 
+			var format = $pmWindow.find('button[name=format]').val();
 			var teamIndex = $pmWindow.find('button[name=team]').val();
 			var team = null;
 			if (app.user.teams[teamIndex]) team = app.user.teams[teamIndex].team;
+			if (!window.BattleFormats[format].team && !team) {
+				app.addPopupMessage("You need to go into the Teambuilder and build a team for this format.");
+				return;
+			}
 
 			var buf = '<form class="battleform pending"><p>Challenging '+Tools.escapeHTML(name)+'...</p>';
 			buf += '<p><label class="label">Format:</label>'+this.renderFormats(format, true)+'</p>';
@@ -470,6 +479,10 @@
 			var teamIndex = $teamButton.val();
 			var team = null;
 			if (app.user.teams[teamIndex]) team = app.user.teams[teamIndex].team;
+			if (!window.BattleFormats[format].team && !team) {
+				app.addPopupMessage("You need to go into the Teambuilder and build a team for this format.");
+				return;
+			}
 
 			$formatButton.addClass('preselected')[0].disabled = true;
 			$teamButton.addClass('preselected')[0].disabled = true;