diff --git a/collects/setup/setup-unit.rkt b/collects/setup/setup-unit.rkt
index fbddaba555..d80c501cf7 100644
--- a/collects/setup/setup-unit.rkt
+++ b/collects/setup/setup-unit.rkt
@@ -970,7 +970,9 @@
             (with-output-to-file p #:exists 'truncate/replace
               (lambda ()
                 (write (hash-map ht cons))
-                (newline))))))))
+                (newline)))))))
+    ;; Flush cached state in the current namespace:
+    (reset-relevant-directories-state!))
 
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