diff --git a/source-registry.lisp b/source-registry.lisp
index 7817d8d637dbf178d7c717e570844001614fe062..e6b51deec7a3762fa8577db5c680097e3a84db2b 100644
--- a/source-registry.lisp
+++ b/source-registry.lisp
@@ -241,7 +241,8 @@ after having found a .asd file? True by default.")
         ((:also-exclude)
          (appendf *source-registry-exclusions* rest))
         ((:default-registry)
-         (inherit-source-registry '(default-source-registry) :register register))
+         (inherit-source-registry
+          '(default-user-source-registry default-system-source-registry) :register register))
         ((:inherit-configuration)
          (inherit-source-registry inherit :register register))
         ((:ignore-inherited-configuration)