diff --git a/build.fsx b/build.fsx
index a8a2beb24..1a1c9fd79 100755
--- a/build.fsx
+++ b/build.fsx
@@ -12,6 +12,8 @@ open Fake.IO.FileSystemOperators
 open Fake.DotNet
 open ``Build-generic``
 
+open System
+open System.IO
 
 
 let product = "Basisregisters Vlaanderen"