diff --git a/src/libstore/globals.cc b/src/libstore/globals.cc
index c75ebdd0e3..7e2624bbf7 100644
--- a/src/libstore/globals.cc
+++ b/src/libstore/globals.cc
@@ -43,7 +43,7 @@ Settings::Settings()
     checkRootReachability = false;
     gcKeepOutputs = false;
     gcKeepDerivations = true;
-    autoOptimiseStore = true;
+    autoOptimiseStore = false;
     envKeepDerivations = false;
 }