diff --git a/R/AddStep.R b/R/AddStep.R
index fece57225aec829518468ceb4911c4e90d5299f5..c34e1b0c8b03dc545c7cffe5e63363a33de1fac4 100644
--- a/R/AddStep.R
+++ b/R/AddStep.R
@@ -5,20 +5,20 @@ AddStep <- function(inputs, step_fun, ...) {
   }
 
   # Check inputs
-  if (any(c('startR_header', 'startR_workflow') %in% class(inputs))) {
+  if (any(c('startR_cube', 'startR_workflow') %in% class(inputs))) {
     inputs <- list(inputs)
     names(inputs) <- 'input1'
   }
   if (is.list(inputs)) {
     if (any(!sapply(inputs, 
-                    function(x) any(c('startR_header', 
+                    function(x) any(c('startR_cube', 
                                       'startR_workflow') %in% class(x))))) {
        stop("Parameter 'inputs' must be one or a list of objects of the class ",
-            "'startR_header' or 'startR_workflow'.")
+            "'startR_cube' or 'startR_workflow'.")
     }
   } else {
     stop("Parameter 'inputs' must be one or a list of objects of the class ",
-         "'startR_header' or 'startR_workflow'.")
+         "'startR_cube' or 'startR_workflow'.")
   }
 
   # Consistency checks
diff --git a/R/ByChunks.R b/R/ByChunks.R
index 933fc71f9147585df7283f92d6bc99625abaf5e5..f9b4027c510ec1abf7fa7d8cef3323f59f689c3f 100644
--- a/R/ByChunks.R
+++ b/R/ByChunks.R
@@ -27,12 +27,12 @@ ByChunks <- function(step_fun, cube_headers, ..., chunks = 'auto',
   MergeArrays <- startR:::.MergeArrays
 
   # Check input headers
-  if ('startR_header' %in% class(cube_headers)) {
+  if ('startR_cube' %in% class(cube_headers)) {
     cube_headers <- list(cube_headers)
   }
   if (!all(sapply(lapply(cube_headers, class), 
-                  function(x) 'startR_header' %in% x))) {
-    stop("All objects passed in 'cube_headers' must be of class 'startR_header', ",
+                  function(x) 'startR_cube' %in% x))) {
+    stop("All objects passed in 'cube_headers' must be of class 'startR_cube', ",
          "as returned by Start().")
   }
 
diff --git a/R/Collect.R b/R/Collect.R
index 44cfda5d4fed0d5fc4e16629d871b659bc58befa..2325d55fcd8834392d647a76c658c04630e17751 100644
--- a/R/Collect.R
+++ b/R/Collect.R
@@ -43,7 +43,8 @@ Collect <- function(startr_exec, wait = TRUE, remove = TRUE) {
   }
   done <- FALSE
   attempt <- 1
-  sum_received_chunks <- 0
+  sum_received_chunks <- sum(grepl('output.*\\.Rds', 
+                                   list.files(ecflow_suite_dir_suite)))
   if (cluster[['bidirectional']]) {
     t_transfer_back <- NA
   } else {
diff --git a/R/Compute.R b/R/Compute.R
index 29d6be023f661af92e6da63fabb709818f05b9be..12c2dcea6cfcfa923f009d37746f2c263b94e5fd 100644
--- a/R/Compute.R
+++ b/R/Compute.R
@@ -55,7 +55,7 @@ Compute <- function(workflow, chunks = 'auto',
                       attr(workflow$fun, 'UseLibraries'),
                       attr(workflow$fun, 'UseAttributes'))
 
-    if (!all(sapply(workflow$inputs, class) == 'startR_header')) {
+    if (!all(sapply(workflow$inputs, class) == 'startR_cube')) {
       stop("Workflows with only one step supported by now.")
     }
     # Run ByChunks with the combined operation
diff --git a/R/Start.R b/R/Start.R
index 168fae710c96085dfd34e22610febae131ea90a9..bac9c6616a8cac0b0c0b1037f5f76f8ddb387515 100644
--- a/R/Start.R
+++ b/R/Start.R
@@ -2868,7 +2868,7 @@ print(str(picked_vars))
                                      FileSelectors = file_selectors,
                                      PatternDim = found_pattern_dim)
                                )
-    attr(data_array, 'class') <- c('startR_cube', attr(data_array, 'class'))
+    attr(data_array, 'class') <- c('startR_array', attr(data_array, 'class'))
     data_array
   } else {
     if (!silent) {
@@ -2898,7 +2898,7 @@ print(str(picked_vars))
                                                    NULL
                                                  })
                                )
-    attr(start_call, 'class') <- c('startR_header', attr(start_call, 'class'))
+    attr(start_call, 'class') <- c('startR_cube', attr(start_call, 'class'))
     start_call
   }
 }
diff --git a/R/Utils.R b/R/Utils.R
index 0d1fdc65f7309b2801c27077541fa639c2bd72bc..699468a059247a6a9f2b0c11e5d75ccaddcedf7a 100644
--- a/R/Utils.R
+++ b/R/Utils.R
@@ -742,8 +742,26 @@ chunk <- function(chunk, n_chunks, selectors) {
         found_chunk <- which(found_chunks_str == paste(chunk_indices_on_file,
                                                        collapse = '_'))[1]
         if (length(found_chunk) > 0) {
-          array_of_chunks[[i]] <- readRDS(paste0(shared_dir, '/',
-                                          chunk_files_original[found_chunk]))
+          num_tries <- 5
+          found <- FALSE
+          try_num <- 1
+          while ((try_num <= num_tries) && !found) {
+            array_of_chunks[[i]] <- try({
+              readRDS(paste0(shared_dir, '/',
+                             chunk_files_original[found_chunk]))
+            })
+            if (('try-error' %in% class(array_of_chunks[[i]]))) {
+              message("Waiting for an incomplete file transfer...")
+              Sys.sleep(5)
+            } else {
+              found <- TRUE
+            } 
+            try_num <- try_num + 1
+          }
+          if (!found) {
+            stop("Could not open one of the chunks. Might be a large chunk ",
+                 "in transfer. Merge aborted, files have been preserved.")
+          }
         }
       }
 
diff --git a/inst/chunking/load_process_save_chunk.R b/inst/chunking/load_process_save_chunk.R
index 8a5843c31819ea3e3ba5e017b4faeedc20012e16..a8a31a888654452737fae18d38ee69a1a59e379d 100644
--- a/inst/chunking/load_process_save_chunk.R
+++ b/inst/chunking/load_process_save_chunk.R
@@ -104,7 +104,11 @@ for (component in names(res)) {
   for (i in 1:total_specified_dims) {
     filename <- paste0(filename, param_dimnames[i], '_', chunk_indices[i], '__')
   }
-  saveRDS(res[[component]], file = paste0(out_dir, '/', filename, '.Rds'))
+  # Saving in a temporary file, then renaming. This way, the polling mechanism
+  # won't transfer back results before the save is completed.
+  saveRDS(res[[component]], file = paste0(out_dir, '/', filename, '.Rds.tmp'))
+  file.rename(paste0(out_dir, '/', filename, '.Rds.tmp'), 
+              paste0(out_dir, '/', filename, '.Rds'))
 }
 rm(res)
 gc()