diff --git a/master_changes.md b/master_changes.md
index cf2b8c056f7..0d5d0a8848d 100644
--- a/master_changes.md
+++ b/master_changes.md
@@ -38,6 +38,7 @@ users)
   * Improve the messages when a package is not up-to-date on opam upgrade [#6272 @kit-ty-kate - fix #6270]
   * Use a non-underline uppercase character to denotate the default when asking a question [#6289 @hannesm @kit-ty-kate - fix #6288]
   * Do not pre-write the answer to questions with the default anwser [#6376 @kit-ty-kate]
+  * Display Windows NTSTATUS exit codes in hex [#6401 @dra27 @MisterDA]
 
 ## Switch
   * [BUG] Fix `opam switch remove <dir>` failure when it is a linked switch [#6276 @btjorge - fix #6275]
diff --git a/src/core/opamProcess.ml b/src/core/opamProcess.ml
index 2d810728ed2..3f25f52e88c 100644
--- a/src/core/opamProcess.ml
+++ b/src/core/opamProcess.ml
@@ -842,10 +842,12 @@ let string_of_result ?(color=`yellow) r =
   Buffer.contents b
 
 let result_summary r =
-  Printf.sprintf "%S exited with code %d%s"
+  Printf.sprintf "%S exited with code %s%s"
     (try OpamStd.List.assoc String.equal "command" r.r_info
      with Not_found -> "command")
-    r.r_code
+    (if Sys.win32 && r.r_code < 0 then
+       Printf.sprintf "0x%08lx" (Int32.of_int r.r_code)
+     else string_of_int r.r_code)
     (if r.r_code = 0 then "" else
      match r.r_stderr, r.r_stdout with
      | [e], _ | [], [e] -> Printf.sprintf " \"%s\"" e