diff --git a/lib/shared/dm-ops/dm-op-utils.js b/lib/shared/dm-ops/dm-op-utils.js
--- a/lib/shared/dm-ops/dm-op-utils.js
+++ b/lib/shared/dm-ops/dm-op-utils.js
@@ -139,6 +139,14 @@
       userIDs.has(peer.userID),
     );
   } else if (recipients.type === 'all_thread_members') {
+    const { threadID } = recipients;
+    if (!threadInfos[threadID]) {
+      console.log(
+        `all_thread_members called for threadID ${threadID}, which is ` +
+          'missing from the ThreadStore. if sending a message soon after ' +
+          'thread creation, consider some_users instead',
+      );
+    }
     const members = threadInfos[recipients.threadID]?.members ?? [];
     const memberIDs = members.map(member => member.id);