diff --git a/_oasis b/_oasis
index 2ea5ba5d..82ecf65e 100644
--- a/_oasis
+++ b/_oasis
@@ -10,7 +10,8 @@ OCamlVersion: >= 4.00.1
 BuildTools:  ocamlbuild
 AlphaFeatures: compiled_setup_ml, ocamlbuild_more_args
 
-XOCamlbuildExtraArgs: "-j 0"
+# cygwin fails with anything else
+XOCamlbuildExtraArgs: "-j 1"
 
 Synopsis:    A modular standard library focused on data structures.
 Description: