diff --git a/client.c b/client.c
index 3f6e5c313..f8607dd6f 100644
--- a/client.c
+++ b/client.c
@@ -697,7 +697,7 @@ client_isvisible(Client *c, int screen)
 {
     Tag *tag;
 
-    if(c->screen != screen)
+    if(!c || c->screen != screen)
         return False;
 
     for(tag = globalconf.screens[screen].tags; tag; tag = tag->next)
diff --git a/widgets/tasklist.c b/widgets/tasklist.c
index 7fe5b5a54..dd4bc3840 100644
--- a/widgets/tasklist.c
+++ b/widgets/tasklist.c
@@ -189,12 +189,15 @@ tasklist_button_press(Widget *widget, XButtonPressedEvent *ev)
                 if(ISVISIBLE_ON_TB(c, widget->statusbar->screen, d->show_all))
                     i++;
 
-            /* first switch tag if client not visible */
-            if(!client_isvisible(c, widget->statusbar->screen))
-                for(i = 0, tag = globalconf.screens[c->screen].tags; tag; tag = tag->next, i++)
-                    if(is_client_tagged(c, tag))
-                        tag_view(c->screen, i);
-            focus(c, True, widget->statusbar->screen);
+            if(c)
+            {
+                /* first switch tag if client not visible */
+                if(!client_isvisible(c, widget->statusbar->screen))
+                    for(i = 0, tag = globalconf.screens[c->screen].tags; tag; tag = tag->next, i++)
+                        if(is_client_tagged(c, tag))
+                           tag_view(c->screen, i);
+                focus(c, True, widget->statusbar->screen);
+            }
 
             return;
         }