diff --git a/lib/awful/client.lua b/lib/awful/client.lua
index ea5457cb0..21f06cc9b 100644
--- a/lib/awful/client.lua
+++ b/lib/awful/client.lua
@@ -974,6 +974,8 @@ function client.incwfact(add, c)
 
     local t = c.screen.selected_tag
     local w = client.idx(c)
+    if not w then return end
+
     local data = t.windowfact or {}
     local colfact = data[w.col] or {}
     local curr = colfact[w.idx] or 1