diff --git a/em_workflows/brt/flow.py b/em_workflows/brt/flow.py
index e2f0e172..e2c6246d 100644
--- a/em_workflows/brt/flow.py
+++ b/em_workflows/brt/flow.py
@@ -734,31 +734,28 @@ def brt_flow(
 
     # Ref: https://github.com/PrefectHQ/prefect/blob/98d33187ecce032defb8ec7a263de32564e7f7f6/src/prefect/futures.py#L43
     callback_result = list()
-    for cb in callback_with_tilt_mov:
+    failed = 0
+    total = len(prim_fps)
+    for fp, cb in zip(fps.result(), callback_with_tilt_mov):
         # Wait for the task to complete
         # It does not mean that future state will be a terminal state
         state = cb.wait()
-        try:
-            if state.is_completed():
-                json.dumps(cb.result())
-                callback_result.append(cb.result())
-        except TypeError:  # can't serialize the item
-            utils.log(f"Following item cannot be added to callback:\n\n{cb.result()}")
-
-    cb = utils.send_callback_body.submit(
+        if state.is_completed():
+            callback_result.append(cb.result())
+        else:
+            callback_result.append(fp.gen_prim_fp_elt("Something went wrong!"))
+            utils.log(
+                f"Following item cannot be added to callback:\n\n{state.result(raise_on_failure=False)}"
+            )
+            failed += 1
+
+    utils.send_callback_body.submit(
         x_no_api=x_no_api,
         token=token,
         callback_url=callback_url,
         files_elts=callback_result,
     )
 
-    if callback_result:
+    if failed < total:
         return Completed(message="At least one callback is correct!")
     return Failed(message="None of the files succeeded!")
-    """
-    # if the callback is not empty (that is one of the files passed), final=success
-    final_state = bool(callback_with_tilt_mov)
-    # Previously, this was done by `set_reference_tasks`
-    # flow.set_reference_tasks([callback_with_tilt_mov])
-    return Completed(message="Success") if final_state else Failed(message="Failed")
-    """
diff --git a/em_workflows/czi/flow.py b/em_workflows/czi/flow.py
index 739b8e87..024f0f60 100644
--- a/em_workflows/czi/flow.py
+++ b/em_workflows/czi/flow.py
@@ -16,13 +16,11 @@
     - Create thumbnail image from zarr label sub-image
 """
 import asyncio
-import json
 from pathlib import Path
 from typing import List, Dict, Optional
 
 import SimpleITK as sitk
 from prefect import flow, task
-from prefect.states import Completed, Failed
 from pytools.HedwigZarrImages import HedwigZarrImage, HedwigZarrImages
 
 from em_workflows.file_path import FilePath
@@ -253,14 +251,15 @@ async def czi_flow(
     )
 
     callback_result = list()
-    for cb in callback_with_zarrs:
+    for fp, cb in zip(fps.result(), callback_with_zarrs):
         state = cb.wait()
-        try:
-            if state.is_completed():
-                json.dumps(cb.result())
-                callback_result.append(cb.result())
-        except TypeError:  # can't serialize the item
-            utils.log(f"Following item cannot be added to callback:\n\n{cb.result()}")
+        if state.is_completed():
+            callback_result.append(cb.result())
+        else:
+            callback_result.append(fp.gen_prim_fp_elt("Something went wrong!"))
+            utils.log(
+                f"Following item cannot be added to callback:\n\n{state.result(raise_on_failure=False)}"
+            )
 
     # we have to filter out incomplete mapped runs before this reduce step
     callback_result = find_thumb_idx.submit(callback=callback_result)
@@ -269,9 +268,5 @@ async def czi_flow(
         x_no_api=x_no_api,
         token=token,
         callback_url=callback_url,
-        files_elts=callback_with_zarrs,
+        files_elts=callback_result,
     )
-
-    if callback_with_zarrs:
-        return Completed(message="At least one callback is correct!")
-    return Failed(message="None of the files succeeded!")
diff --git a/em_workflows/dm_conversion/flow.py b/em_workflows/dm_conversion/flow.py
index 92073f65..ef868ab8 100644
--- a/em_workflows/dm_conversion/flow.py
+++ b/em_workflows/dm_conversion/flow.py
@@ -1,9 +1,7 @@
-import json
 from pathlib import Path
 from typing import Optional
 
 from prefect import flow, task, unmapped
-from prefect.states import Completed, Failed
 from pytools.meta import is_int16
 from pytools.convert import file_to_uint8
 
@@ -262,14 +260,15 @@ def dm_flow(
     )
 
     callback_result = list()
-    for cb in callback_with_keyimgs:
+    for fp, cb in zip(fps.result(), callback_with_keyimgs):
         state = cb.wait()
-        try:
-            if state.is_completed():
-                json.dumps(cb.result())
-                callback_result.append(cb.result())
-        except TypeError:  # can't serialize the item
-            utils.log(f"Following item cannot be added to callback:\n\n{cb.result()}")
+        if state.is_completed():
+            callback_result.append(cb.result())
+        else:
+            callback_result.append(fp.gen_prim_fp_elt("Something went wrong!"))
+            utils.log(
+                f"Following item cannot be added to callback:\n\n{state.result(raise_on_failure=False)}"
+            )
 
     utils.send_callback_body.submit(
         x_no_api=x_no_api,
@@ -277,7 +276,3 @@ def dm_flow(
         callback_url=callback_url,
         files_elts=callback_result,
     )
-
-    if callback_result:
-        return Completed(message="At least one callback is correct!")
-    return Failed(message="None of the files succeeded!")
diff --git a/em_workflows/lrg_2d_rgb/flow.py b/em_workflows/lrg_2d_rgb/flow.py
index fba8bf60..2637257a 100644
--- a/em_workflows/lrg_2d_rgb/flow.py
+++ b/em_workflows/lrg_2d_rgb/flow.py
@@ -1,11 +1,9 @@
-import json
 from typing import Dict, Optional
 from pathlib import Path
 
 import SimpleITK as sitk
 from pytools import HedwigZarrImage, HedwigZarrImages
 from prefect import flow, task
-from prefect.states import Completed, Failed
 
 from em_workflows.utils import utils
 from em_workflows.utils import neuroglancer as ng
@@ -192,14 +190,15 @@ def lrg_2d_flow(
     )
 
     callback_result = list()
-    for cb in callback_with_pyramids:
+    for fp, cb in zip(fps.result(), callback_with_pyramids):
         state = cb.wait()
-        try:
-            if state.is_completed():
-                json.dumps(cb.result())
-                callback_result.append(cb.result())
-        except TypeError:  # can't serialize the item
-            utils.log(f"Following item cannot be added to callback:\n\n{cb.result()}")
+        if state.is_completed():
+            callback_result.append(cb.result())
+        else:
+            callback_result.append(fp.gen_prim_fp_elt("Something went wrong!"))
+            utils.log(
+                f"Following item cannot be added to callback:\n\n{state.result(raise_on_failure=False)}"
+            )
 
     utils.send_callback_body.submit(
         x_no_api=x_no_api,
@@ -207,7 +206,3 @@ def lrg_2d_flow(
         callback_url=callback_url,
         files_elts=callback_result,
     )
-
-    if callback_result:
-        return Completed(message="At least one callback is correct!")
-    return Failed(message="None of the files succeeded!")
diff --git a/em_workflows/sem_tomo/flow.py b/em_workflows/sem_tomo/flow.py
index a6c6a374..e19ae378 100644
--- a/em_workflows/sem_tomo/flow.py
+++ b/em_workflows/sem_tomo/flow.py
@@ -21,13 +21,11 @@
 
 import glob
 import math
-import json
 from pathlib import Path
 from typing import Dict, Optional
 from natsort import os_sorted
 
 from prefect import flow, task, unmapped
-from prefect.states import Completed, Failed
 from pytools.HedwigZarrImages import HedwigZarrImages
 
 from em_workflows.utils import utils
@@ -386,14 +384,15 @@ def sem_tomo_flow(
     )
 
     callback_result = list()
-    for cb in callback_with_corr_movies:
+    for fp, cb in zip(fps.result(), callback_with_corr_movies):
         state = cb.wait()
-        try:
-            if state.is_completed():
-                json.dumps(cb.result())
-                callback_result.append(cb.result())
-        except TypeError:  # can't serialize the item
-            utils.log(f"Following item cannot be added to callback:\n\n{cb.result()}")
+        if state.is_completed():
+            callback_result.append(cb.result())
+        else:
+            callback_result.append(fp.gen_prim_fp_elt("Something went wrong!"))
+            utils.log(
+                f"Following item cannot be added to callback:\n\n{state.result(raise_on_failure=False)}"
+            )
 
     utils.send_callback_body.submit(
         x_no_api=x_no_api,
@@ -401,7 +400,3 @@ def sem_tomo_flow(
         callback_url=callback_url,
         files_elts=callback_result,
     )
-
-    if callback_result:
-        return Completed(message="At least one callback is correct!")
-    return Failed(message="None of the files succeeded!")