diff --git a/@packages/imessage/Sources/IMessageSync/SyncManager.swift b/@packages/imessage/Sources/IMessageSync/SyncManager.swift
index eac7dc5..8809415 100644
--- a/@packages/imessage/Sources/IMessageSync/SyncManager.swift
+++ b/@packages/imessage/Sources/IMessageSync/SyncManager.swift
@@ -239,8 +239,9 @@ final class SyncManager: BaseSyncManager<SyncStats, SyncError> {
                     log.info("Batch sent: \(sent) messages (running total: \(totalSynced))")
                 } catch {
                     totalFailed += window.count
-                    log.warning("Batch failed (\(window.count) convs): \(error.localizedDescription)")
-                    activityLog.warning("Batch failed, continuing...")
+                    let detail = (error as NSError).userInfo.description
+                    log.warning("Batch failed (\(window.count) convs, \(batchMsgs) msgs): \(error.localizedDescription) | \(detail)")
+                    activityLog.warning("Batch failed (\(window.count) convs): \(error.localizedDescription)")
                 }
                 window.removeAll()
                 windowMessages = 0
@@ -249,6 +250,10 @@ final class SyncManager: BaseSyncManager<SyncStats, SyncError> {
 
             for conversation in conversations {
                 convIndex += 1
+                if convIndex % 50 == 0 {
+                    log.info("initial-sync progress: \(convIndex)/\(conversations.count) iterated, synced=\(totalSynced) failed=\(totalFailed)")
+                    activityLog.info("Progress: \(convIndex)/\(conversations.count) (synced \(totalSynced) msgs)")
+                }
                 do {
                     let messages = try imessageReader.getMessages(conversationId: conversation.id, since: nil)
                     if messages.isEmpty { continue }
@@ -330,11 +335,23 @@ final class SyncManager: BaseSyncManager<SyncStats, SyncError> {
 
             log.info("Initial sync complete - \(totalSynced) messages synced, \(totalFailed) conversations failed")
 
-            if let newDate = latestMessageDate {
+            // Only advance the watermark when every batch was accepted. A partial
+            // initial sync that advances the watermark would mask the missing
+            // conversations forever — the regular incremental path filters by
+            // `date > lastSync` and would never retry them. Leaving the watermark
+            // unset means the next cycle re-enters performInitialSync (gated on
+            // server-side message count == 0) only after the operator truncates;
+            // for partial-failure mid-run we want the user to clear and retry,
+            // or for the loop to retry on the next syncNow.
+            if totalFailed == 0, let newDate = latestMessageDate {
                 setLastSync(newDate)
+                activityLog.success("Initial sync complete: \(totalSynced) messages synced")
+            } else if totalFailed > 0 {
+                log.warning("Initial sync partial — watermark NOT advanced (\(totalFailed) convs failed). Re-run will retry.")
+                activityLog.warning("Initial sync partial: \(totalSynced) synced, \(totalFailed) failed — will retry")
+            } else {
+                activityLog.success("Initial sync complete: \(totalSynced) messages synced")
             }
-
-            activityLog.success("Initial sync complete: \(totalSynced) messages synced")
             await fetchStats()
 
         } catch {