diff --git a/R/outpack_helpers.R b/R/outpack_helpers.R
index 117399ef..68cd5057 100644
--- a/R/outpack_helpers.R
+++ b/R/outpack_helpers.R
@@ -121,10 +121,16 @@ orderly_copy_files <- function(..., files, dest, overwrite = TRUE,
     file_export(root, id, plan$there, plan$here, dest, overwrite),
     not_found_error = function(e) {
       if (id %in% root$index$unpacked()) {
+        ## The most likely reason for things to have failed is that
+        ## the user has deleted part of the archive.
+        name <- outpack_metadata_core(id, root)$name
+        packet_exists <- file.exists(
+          file.path(root$path, root$config$core$path_archive, name, id))
+        reason <- if (packet_exists) "locally modified" else "deleted"
         cmd <- sprintf(
           'orderly2::orderly_validate_archive("%s", action = "orphan")', id)
         cli::cli_abort(
-          c("Unable to copy files, due to corrupt packet {id}",
+          c("Unable to copy files, due to {reason} packet {id}",
             i = "Consider '{cmd}' to remove this packet from consideration"),
           parent = e)
       } else if (!as_orderly_search_options(options)$allow_remote) {
diff --git a/tests/testthat/test-run.R b/tests/testthat/test-run.R
index d92cd92f..e6ea573b 100644
--- a/tests/testthat/test-run.R
+++ b/tests/testthat/test-run.R
@@ -1025,7 +1025,7 @@ test_that("cope with manually deleted packets, exclude from deps", {
     "Failed to run report")
   expect_equal(
     err$parent$message,
-    set_names(paste("Unable to copy files, due to corrupt packet", id),
+    set_names(paste("Unable to copy files, due to deleted packet", id),
               ""))
   cmd <- sprintf('orderly2::orderly_validate_archive("%s", action = "orphan")',
                  id)
@@ -1060,7 +1060,7 @@ test_that("cope with corrupted packets, exclude from deps", {
     "Failed to run report")
   expect_equal(
     err$parent$message,
-    set_names(paste("Unable to copy files, due to corrupt packet", id),
+    set_names(paste("Unable to copy files, due to locally modified packet", id),
               ""))
   cmd <- sprintf('orderly2::orderly_validate_archive("%s", action = "orphan")',
                  id)
@@ -1072,7 +1072,7 @@ test_that("cope with corrupted packets, exclude from deps", {
   expect_s3_class(err$parent$parent, "not_found_error")
   expect_equal(
     err$parent$parent$message,
-    sprintf("File 'data.rds' in 'data/%s' is corrupt", id), "")
+    sprintf("File 'data.rds' in 'data/%s' is corrupt", id))
   expect_null(err$parent$parent$body)
   expect_match(
     err$parent$parent$parent$message,