diff --git a/compiler/nim.cfg b/compiler/nim.cfg
index 853a657b39..926cb4c28f 100644
--- a/compiler/nim.cfg
+++ b/compiler/nim.cfg
@@ -6,6 +6,7 @@ define:booting
 define:nimcore
 define:nimPreviewFloatRoundtrip
 define:nimPreviewSlimSystem
+threads:off
 
 #import:"$projectpath/testability"