diff --git a/R/outpack_config.R b/R/outpack_config.R
index 01da4f76..e15115b3 100644
--- a/R/outpack_config.R
+++ b/R/outpack_config.R
@@ -187,7 +187,7 @@ config_set_path_archive <- function(value, root) {
     path_archive_old <- file.path(root$path, config$core$path_archive)
     if (fs::dir_exists(path_archive_old)) {
       path_archive_new <- file.path(root$path, value)
-      assert_relative_path(value, name = "path_archive", workdir = root$path)
+      assert_relative_path(value, name = "'path_archive'", workdir = root$path)
       assert_directory_does_not_exist(path_archive_new)
       fs::dir_copy(path_archive_old, path_archive_new)
       fs::dir_delete(path_archive_old)
@@ -195,7 +195,7 @@ config_set_path_archive <- function(value, root) {
     config$core$path_archive <- value
   } else {
     path_archive <- file.path(root$path, value)
-    assert_relative_path(value, name = "path_archive", workdir = root$path)
+    assert_relative_path(value, name = "'path_archive'", workdir = root$path)
     assert_directory_does_not_exist(path_archive)
     tryCatch({
       fs::dir_create(path_archive)
diff --git a/R/util_assert.R b/R/util_assert.R
index acb0e4e3..28372ea2 100644
--- a/R/util_assert.R
+++ b/R/util_assert.R
@@ -109,7 +109,7 @@ assert_relative_path <- function(files, name, workdir, call = NULL) {
     n <- cli::qty(sum(err))
     ## TODO: try and relativise - use path_has_parent and path_rel
     cli::cli_abort(
-      c("{name}{n}{?s} must be relative path{?s}",
+      c("{name}{n}{?s} must be {?a/} relative path{?s}",
         set_names(files[err], "x"),
         i = "Path was relative to directory '{workdir}'"),
       call = call)
diff --git a/tests/testthat/test-outpack-config.R b/tests/testthat/test-outpack-config.R
index 68a0fa5a..e94524f5 100644
--- a/tests/testthat/test-outpack-config.R
+++ b/tests/testthat/test-outpack-config.R
@@ -271,7 +271,7 @@ test_that("Archive is not added if file store is corrupt", {
 test_that("Validates path_archive", {
   root <- create_temporary_root(path_archive = NULL, use_file_store = TRUE)
   expect_error(orderly_config_set(core.path_archive = "/archive", root = root),
-               "'path_archive' must be relative path")
+               "'path_archive' must be a relative path")
   expect_null(root$config$core$path_archive)
 
   dir.create(file.path(root$path, "archive"))
@@ -281,7 +281,7 @@ test_that("Validates path_archive", {
 
   orderly_config_set(core.path_archive = "new-archive", root = root)
   expect_error(orderly_config_set(core.path_archive = "/archive", root = root),
-               "'path_archive' must be relative path")
+               "'path_archive' must be a relative path")
   expect_error(orderly_config_set(core.path_archive = "archive", root = root),
                "Directory already exists")
   expect_equal(root$config$core$path_archive, "new-archive")
diff --git a/tests/testthat/test-util-assert.R b/tests/testthat/test-util-assert.R
index 28faabb0..317905c2 100644
--- a/tests/testthat/test-util-assert.R
+++ b/tests/testthat/test-util-assert.R
@@ -108,7 +108,7 @@ test_that("assert_is_directory", {
 test_that("assert_relative_path", {
   workdir <- getwd()
   expect_error(assert_relative_path(getwd(), "File", workdir),
-               "File must be relative path",
+               "File must be a relative path",
                fixed = TRUE)
   expect_silent(assert_relative_path("relpath", "File", workdir))
   expect_silent(assert_relative_path("a/b/c", "File", workdir))