diff --git a/opam/opam b/opam/opam
index f60fee39900551bb31fa7b8f19d69106431bc618..d20af2f6f82340c4314295461fe5a7fc29c61abd 100644
--- a/opam/opam
+++ b/opam/opam
@@ -135,3 +135,7 @@ messages: [
   "The Frama-C/Wp native support for Coq is now deprecated (use TIP or Why-3 instead)."
   {coq:installed}
 ]
+
+post-messages: [
+  "Why3 provers setup: rm -r ~/.why3.conf ; why3 config --detect"
+]