diff --git a/builtin/fetch.c b/builtin/fetch.c
index d427adea61..49495be0b6 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -1649,7 +1649,7 @@ static void ref_transaction_rejection_handler(const char *refname,
 					      const char *old_target UNUSED,
 					      const char *new_target UNUSED,
 					      enum ref_transaction_error err,
-					      const char *details UNUSED,
+					      const char *details,
 					      void *cb_data)
 {
 	struct ref_rejection_data *data = cb_data;
@@ -1674,9 +1674,11 @@ static void ref_transaction_rejection_handler(const char *refname,
 			"branches"), data->remote_name);
 		data->conflict_msg_shown = true;
 	} else {
-		const char *reason = ref_transaction_error_msg(err);
-
-		error(_("fetching ref %s failed: %s"), refname, reason);
+		if (details)
+			error("%s", details);
+		else
+			error(_("fetching ref %s failed: %s"),
+			      refname, ref_transaction_error_msg(err));
 	}
 
 	*data->retcode = 1;
diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index ce1c23684e..c69afb5a60 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -1516,7 +1516,7 @@ test_expect_success REFFILES 'existing reference lock in repo' '
 		git remote add origin ../base &&
 		touch refs/heads/foo.lock &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "error: fetching ref refs/heads/foo failed: reference already exists" err &&
+		test_grep -e "error: cannot lock ref ${SQ}refs/heads/foo${SQ}: Unable to create" -e "refs/heads/foo.lock${SQ}: File exists." err &&
 		git rev-parse refs/heads/main >expect &&
 		git rev-parse refs/heads/branch >actual &&
 		test_cmp expect actual
@@ -1530,7 +1530,7 @@ test_expect_success CASE_INSENSITIVE_FS,REFFILES 'F/D conflict on case insensiti
 		cd case_insensitive &&
 		git remote add origin -- ../case_sensitive_fd &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "failed: refname conflict" err &&
+		test_grep "cannot process ${SQ}refs/remotes/origin/foo${SQ} and ${SQ}refs/remotes/origin/foo/bar${SQ} at the same time" err &&
 		git rev-parse refs/heads/main >expect &&
 		git rev-parse refs/heads/foo/bar >actual &&
 		test_cmp expect actual
@@ -1544,7 +1544,7 @@ test_expect_success CASE_INSENSITIVE_FS,REFFILES 'D/F conflict on case insensiti
 		cd case_insensitive &&
 		git remote add origin -- ../case_sensitive_df &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "failed: refname conflict" err &&
+		test_grep "cannot lock ref ${SQ}refs/remotes/origin/foo${SQ}: there is a non-empty directory ${SQ}./refs/remotes/origin/foo${SQ} blocking reference ${SQ}refs/remotes/origin/foo${SQ}" err &&
 		git rev-parse refs/heads/main >expect &&
 		git rev-parse refs/heads/Foo/bar >actual &&
 		test_cmp expect actual
@@ -1658,7 +1658,7 @@ test_expect_success REFFILES "FETCH_HEAD is updated even if ref updates fail" '
 		git remote add origin ../base &&
 		>refs/heads/foo.lock &&
 		test_must_fail git fetch -f origin "refs/heads/*:refs/heads/*" 2>err &&
-		test_grep "error: fetching ref refs/heads/foo failed: reference already exists" err &&
+		test_grep -e "error: cannot lock ref ${SQ}refs/heads/foo${SQ}: Unable to create" -e "refs/heads/foo.lock${SQ}: File exists." err &&
 		test_grep "branch ${SQ}branch${SQ} of ../base" FETCH_HEAD &&
 		test_grep "branch ${SQ}foo${SQ} of ../base" FETCH_HEAD
 	)