diff --git a/packages/fat-filesystem/fat-filesystem.0.13.0/opam b/packages/fat-filesystem/fat-filesystem.0.13.0/opam
index b30b1dd9d9f..42507eca00f 100644
--- a/packages/fat-filesystem/fat-filesystem.0.13.0/opam
+++ b/packages/fat-filesystem/fat-filesystem.0.13.0/opam
@@ -18,6 +18,7 @@ depends: [
   "mirage-block-unix" {>= "2.5.0"}
   "io-page-unix" {>= "2.0.0"}
   "re" {>= "1.7.2"}
+  "result"
   "cmdliner"
   "astring"
   "alcotest" {with-test}