diff --git a/lib/awful/widget/tasklist.lua b/lib/awful/widget/tasklist.lua
index a0605834..ccae7fa1 100644
--- a/lib/awful/widget/tasklist.lua
+++ b/lib/awful/widget/tasklist.lua
@@ -181,6 +181,9 @@ function tasklist.new(screen, filter, buttons, style, update_function, base_widg
             queued_update = true
         end
     end
+    function w._unmanage(c)
+        data[c] = nil
+    end
     if instances == nil then
         instances = {}
         local function us(s)
@@ -219,7 +222,14 @@ function tasklist.new(screen, filter, buttons, style, update_function, base_widg
         capi.client.connect_signal("property::hidden", u)
         capi.client.connect_signal("tagged", u)
         capi.client.connect_signal("untagged", u)
-        capi.client.connect_signal("unmanage", u)
+        capi.client.connect_signal("unmanage", function(c)
+            u(c)
+            for s, i in pairs(instances) do
+                for _, tlist in pairs(i) do
+                    tlist._unmanage(c)
+                end
+            end
+        end)
         capi.client.connect_signal("list", u)
         capi.client.connect_signal("focus", u)
         capi.client.connect_signal("unfocus", u)