diff --git a/src/env_universal_common.cpp b/src/env_universal_common.cpp
index 36f69cc72..bdbe8c5ca 100644
--- a/src/env_universal_common.cpp
+++ b/src/env_universal_common.cpp
@@ -1582,7 +1582,12 @@ universal_notifier_t::notifier_strategy_t universal_notifier_t::resolve_default_
     return strategy_notifyd;
 #elif defined(__CYGWIN__)
     return strategy_shmem_polling;
-#elif defined(SIGIO)
+#elif defined(SIGIO) && (defined(__APPLE__) || defined(__BSD__) || defined(__linux__))
+    // The SIGIO notifier relies on an extremely specific interaction between signal handling and
+    // O_ASYNC writes, and doesn't excercise codepaths that are particularly well explored on all
+    // POSIX and POSIX-like systems, so we only explicitly enable it on platforms where it's known
+    // to work. See discussion in #6585 for examples of breakage.
+    //
     // The SIGIO notifier does not yet work on WSL. See #7429
     if (is_windows_subsystem_for_linux()) {
         return strategy_named_pipe;