diff --git a/stack-windows.yaml b/stack-windows.yaml
index bdacbec314..fc81c3454a 100644
--- a/stack-windows.yaml
+++ b/stack-windows.yaml
@@ -25,6 +25,7 @@ extra-deps:
 - bloomfilter-2.0.1.0
 - torrent-10000.1.1
 - yesod-default-1.2.0
+- unix-compat-0.5
 explicit-setup-deps:
   git-annex: true
 resolver: lts-9.10