diff --git a/R/distance_helpers.R b/R/distance_helpers.R
index 640d58b..09c6cc9 100644
--- a/R/distance_helpers.R
+++ b/R/distance_helpers.R
@@ -118,7 +118,7 @@ nearest_neighbor_summary_single_impl = function(csd, phenotypes,
     dplyr::ungroup()
 
   # Optionally save details with a subset of columns
-  if (!is.null(details_path)) {
+  if (!is.null(details_path) && length(details_path) > 0 && nrow(distances) > 0) {
     distances_subset = distances %>%
       dplyr::select(!!.by, `Cell ID`, `Cell X Position`, `Cell Y Position`,
                     !!field_col,
@@ -307,7 +307,7 @@ count_within_summary_impl = function(csd, phenotypes, radii,
     dplyr::ungroup()
 
   # Optionally save details with a subset of columns
-  if (!is.null(category_path) && nrow(counts) > 0) {
+  if (!is.null(category_path) && length(category_path) > 0 && nrow(counts) > 0) {
     counts_subset = counts %>%
       dplyr::select(!!.by, `Cell ID`, `Cell X Position`, `Cell Y Position`,
                     !!field_col,
diff --git a/inst/analysis_app/formatters.R b/inst/analysis_app/formatters.R
index b3e35f8..0b6e3a3 100644
--- a/inst/analysis_app/formatters.R
+++ b/inst/analysis_app/formatters.R
@@ -306,7 +306,7 @@ format_cleanup = function(slide_id_prefix, use_regex, has) {
 
   # Now slide_id_prefix is a valid regex. We still have to double-escape \
   # to put it into a string literal.
-  slide_id_prefix = stringr::str_replace(slide_id_prefix,
+  slide_id_prefix = stringr::str_replace_all(slide_id_prefix,
                                          stringr::fixed('\\'), '\\\\')
 
   # Note: Don't use mutate() in cleanup(),