diff --git a/build-constraints.yaml b/build-constraints.yaml
index ab439ac9..c3467fb5 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -4690,7 +4690,7 @@ packages:
         - phatsort
         - queue-sheet
         - redact
-        - ttc
+        - ttc < 1.5 # https://github.com/commercialhaskell/stackage/issues/7640
 
     "Jasper Woudenberg <mail@jasperwoudenberg.com> @jwoudenberg":
         - bugsnag-hs