diff --git a/datman/src/backup.rs b/datman/src/backup.rs
index d980858..9c32975 100644
--- a/datman/src/backup.rs
+++ b/datman/src/backup.rs
@@ -2,7 +2,7 @@ use crate::descriptor_config::{SourceDescriptor, SourceDescriptorInner, VirtualS
 use crate::pointer_names::{get_pointer_name_at, POINTER_NAME_DATETIME_SPLITTER};
 use chrono::{DateTime, Utc};
 use dashmap::DashSet;
-use eyre::{bail, eyre, Context, ContextCompat};
+use eyre::{bail, eyre, Context, ContextCompat, ensure};
 use indicatif::ProgressStyle;
 use patricia_tree::PatriciaMap;
 use std::borrow::Cow;
@@ -309,6 +309,9 @@ async fn backup_dir_sources(
         StoragePipeline::launch_new(4, pwc.clone(), new_unflushed_chunks).await?;
 
     let dir_sources2 = &dir_sources;
+    let mut submitted = 0;
+    let mut completed = 0;
+    let submitted_mut = &mut submitted;
     let (submitter_task, receiver_task) = tokio::join!(
         async move {
             let pipeline_job_tx = pipeline_job_tx;
@@ -325,6 +328,7 @@ async fn backup_dir_sources(
                             ))
                             .await
                             .map_err(|_| eyre!("unable to send to pipeline."))?;
+                        *submitted_mut += 1;
                     }
                 }
             }
@@ -337,6 +341,7 @@ async fn backup_dir_sources(
                 pipeline.next_result().await
             {
                 chunk_file_maps[dir_source_idx].insert_str(&job_id, (rec_chunk_ref, real_size));
+                completed += 1;
                 Span::current().pb_inc(1);
             }
             // eprintln!("fin rec");
@@ -347,6 +352,8 @@ async fn backup_dir_sources(
     submitter_task?;
     receiver_task?;
 
+    ensure!(completed == submitted, "completed: {completed:?} != submitted {submitted:?}");
+
     assert_eq!(dir_sources.len(), chunk_file_maps.len());
 
     let chunkmaps = pipeline.finish_into_chunkmaps().await?;
diff --git a/yama_pile/src/tree.rs b/yama_pile/src/tree.rs
index 5dd1267..f860494 100644
--- a/yama_pile/src/tree.rs
+++ b/yama_pile/src/tree.rs
@@ -411,7 +411,7 @@ pub fn assemble_tree_from_scan_entries(
             } => {
                 let (content, size) = chunkings
                     .remove(&key_string)
-                    .context("bad chunkings PMap: missing entry")?;
+                    .with_context(|| format!("bad chunkings PMap: missing entry: {key_string:?}"))?;
 
                 // note: for the root, this inserts the root file entry as a child called "" within a fake root 'directory'.
                 // That's fine. We'll patch this up later.