diff --git a/Stackage/Config.hs b/Stackage/Config.hs
index cd71b55d..dc1faef6 100644
--- a/Stackage/Config.hs
+++ b/Stackage/Config.hs
@@ -140,6 +140,9 @@ defaultStablePackages = unPackageMap $ execWriter $ do
     -- https://github.com/fpco/stackage/issues/46
     addRange "Michael Snoyman" "QuickCheck" "< 2.6"
     addRange "Michael Snoyman" "syb" "< 0.4"
+
+    -- https://github.com/fpco/stackage/issues/49
+    addRange "Michael Snoyman" "NumInstances" "< 1.2"
   where
     add maintainer package = addRange maintainer package "-any"
     addRange maintainer package range =