diff --git a/ghc/docs/users_guide/runtime_control.sgml b/ghc/docs/users_guide/runtime_control.sgml
index 50add02eb2b59476ec621021bb5b09b3e13b18b3..a3809d5475e5b1b9848cbc0fb5e77cc76c3ed236 100644
--- a/ghc/docs/users_guide/runtime_control.sgml
+++ b/ghc/docs/users_guide/runtime_control.sgml
@@ -408,6 +408,10 @@ hooks, but by writing your own version and linking it on the GHC
 command line, you can override the defaults.
 </Para>
 
+<Para>
+Owing to the vagaries of DLL linking, these hooks don't work under Windows.
+</Para>
+
 <Para>
 The function <Function>defaultsHook</Function><IndexTerm><Primary>defaultHook</Primary></IndexTerm> lets you change various
 RTS options.  The commonest use for this is to give your program a