Unable to start ComfyUI Desktop v0.4.74 (SOLVED)

Hi all,

My system was working fine, but then I tried to install the new WAN 2.2-ANIMATE official workflow from the Templates (ie. the official browse templates).

I clicked to download all the missing models. Then it said various custom nodes were missing so I went into the Manager and it said to update KJNODES. I clicked to update. It said to restart.

Now, comfy UI won’t start. It says “Unable to start ComfyUI Desktop v0.4.74”. I clicked TROUBLESHOT, then it says no error, then I click “Continue” and it very very quickly displays a red “unable to continue” and restarts. Then it tries to start up and returns to “Unable to start ComfyUI Desktop v0.4.74”.

Here’s the log:

[2025-09-25 10:30:15.377] [info] Adding extra search path custom_nodes C:\Users\toby\Documents\ComfyUI\custom_nodes

[2025-09-25 10:30:15.378] [info] Adding extra search path download_model_base C:\Users\toby\Documents\ComfyUI\models
Adding extra search path custom_nodes C:\Users\toby\AppData\Local\Programs@comfyorgcomfyui-electron\resources\ComfyUI\custom_nodes
Setting output directory to: C:\Users\toby\Documents\ComfyUI\output
Setting input directory to: C:\Users\toby\Documents\ComfyUI\input
Setting user directory to: C:\Users\toby\Documents\ComfyUI\user

[2025-09-25 10:30:16.807] [error] WARNING: Ignoring invalid distribution ~%mpy (C:\Users\toby\Documents\ComfyUI.venv\Lib\site-packages)

[2025-09-25 10:30:16.808] [error] WARNING: Ignoring invalid distribution ~ (C:\Users\toby\Documents\ComfyUI.venv\Lib\site-packages)
WARNING: Ignoring invalid distribution ~-mpy (C:\Users\toby\Documents\ComfyUI.venv\Lib\site-packages)
WARNING: Ignoring invalid distribution ~0mpy (C:\Users\toby\Documents\ComfyUI.venv\Lib\site-packages)
WARNING: Ignoring invalid distribution ~1mpy (C:\Users\toby\Documents\ComfyUI.venv\Lib\site-packages)
WARNING: Ignoring invalid distribution ~=mpy (C:\Users\toby\Documents\ComfyUI.venv\Lib\site-packages)

[2025-09-25 10:30:16.810] [error] WARNING: Ignoring invalid distribution ~umpy (C:\Users\toby\Documents\ComfyUI.venv\Lib\site-packages)
WARNING: Ignoring invalid distribution ~~mpy (C:\Users\toby\Documents\ComfyUI.venv\Lib\site-packages)

[2025-09-25 10:30:17.445] [info] [START] Security scan
[DONE] Security scan

ComfyUI-Manager: installing dependencies done.

[2025-09-25 10:30:17.446] [info] ** ComfyUI startup time: 2025-09-25 10:30:17.444
** Platform: Windows
** Python version: 3.12.9 (main, Feb 12 2025, 14:52:31) [MSC v.1942 64 bit (AMD64)]
** Python executable: C:\Users\toby\Documents\ComfyUI.venv\Scripts\python.exe
** ComfyUI Path: C:\Users\toby\AppData\Local\Programs@comfyorgcomfyui-electron\resources\ComfyUI
** ComfyUI Base Folder Path: C:\Users\toby\AppData\Local\Programs@comfyorgcomfyui-electron\resources\ComfyUI
** User directory: C:\Users\toby\Documents\ComfyUI\user
** ComfyUI-Manager config path: C:\Users\toby\Documents\ComfyUI\user\default\ComfyUI-Manager\config.ini
[2025-09-25 10:30:17.447] [info]
** Log path: C:\Users\toby\Documents\ComfyUI\user\comfyui.log

[2025-09-25 10:30:17.841] [error] WARNING: Ignoring invalid distribution ~%mpy (C:\Users\toby\Documents\ComfyUI.venv\Lib\site-packages)

[2025-09-25 10:30:17.843] [error] WARNING: Ignoring invalid distribution ~ (C:\Users\toby\Documents\ComfyUI.venv\Lib\site-packages)
WARNING: Ignoring invalid distribution ~-mpy (C:\Users\toby\Documents\ComfyUI.venv\Lib\site-packages)
WARNING: Ignoring invalid distribution ~0mpy (C:\Users\toby\Documents\ComfyUI.venv\Lib\site-packages)
WARNING: Ignoring invalid distribution ~1mpy (C:\Users\toby\Documents\ComfyUI.venv\Lib\site-packages)
WARNING: Ignoring invalid distribution ~=mpy (C:\Users\toby\Documents\ComfyUI.venv\Lib\site-packages)
WARNING: Ignoring invalid distribution ~umpy (C:\Users\toby\Documents\ComfyUI.venv\Lib\site-packages)

[2025-09-25 10:30:17.844] [error] WARNING: Ignoring invalid distribution ~~mpy (C:\Users\toby\Documents\ComfyUI.venv\Lib\site-packages)

[2025-09-25 10:30:18.161] [info]
#######################################################################
[ComfyUI-Manager] Starting dependency installation/(de)activation for the extension

[2025-09-25 10:30:18.162] [info]

[2025-09-25 10:30:21.564] [error]
0%| | 0.00/24.7M [00:00<?, ?B/s]
[2025-09-25 10:30:21.665] [error]
4%|▍ | 950k/24.7M [00:00<00:02, 9.43MB/s]
[2025-09-25 10:30:21.765] [error]
37%|███▋ | 9.08M/24.7M [00:00<00:00, 51.4MB/s]
[2025-09-25 10:30:21.866] [error]
79%|███████▉ | 19.6M/24.7M [00:00<00:00, 75.7MB/s]
[2025-09-25 10:30:21.917] [error]
100%|██████████| 24.7M/24.7M [00:00<00:00, 70.2MB/s]
[2025-09-25 10:30:21.918] [error]

[2025-09-25 10:30:21.922] [info] [ERROR] Failed to execute management script: [‘comfyui-kjnodes’, ‘#LAZY-CNR-SWITCH-SCRIPT’, ‘https://cdn.comfy.org/kijai/comfyui-kjnodes/1.1.6/node.zip’, ‘C:\Users\toby\Documents\ComfyUI\custom_nodes\comfyui-kjnodes’, ‘C:\Users\toby\Documents\ComfyUI\custom_nodes\comfyui-kjnodes’, False, ‘C:\Users\toby\Documents\ComfyUI\custom_nodes’, ‘C:\Users\toby\Documents\ComfyUI\.venv\Scripts\python.exe’]
/ [Errno 13] Permission denied: ‘C:\Users\toby\Documents\ComfyUI\custom_nodes\comfyui-kjnodes\docs\images\2024-04-03_20_49_29-ComfyUI.png’

[2025-09-25 10:30:21.923] [error] Failed to execute startup-script: C:\Users\toby\AppData\Local\Programs@comfyorgcomfyui-electron\resources\ComfyUI\custom_nodes\ComfyUI-Manager\prestartup_script.py / [WinError 5] Access is denied: ‘C:\Users\toby\Documents\ComfyUI\user\default\ComfyUI-Manager\startup-scripts\install-scripts.txt’

[2025-09-25 10:30:21.923] [info]
Prestartup times for custom nodes:
6.5 seconds (PRESTARTUP FAILED): C:\Users\toby\AppData\Local\Programs@comfyorgcomfyui-electron\resources\ComfyUI\custom_nodes\ComfyUI-Manager

[2025-09-25 10:30:21.924] [info] WARNING: Potential Error in code: Torch already imported, torch should never be imported before this point.

[2025-09-25 10:30:21.932] [info] Checkpoint files will always be loaded safely.

[2025-09-25 10:30:21.975] [error] Traceback (most recent call last):

[2025-09-25 10:30:21.976] [error] File “C:\Users\toby\AppData\Local\Programs@comfyorgcomfyui-electron\resources\ComfyUI\main.py”, line 147, in
import execution
File “C:\Users\toby\AppData\Local\Programs@comfyorgcomfyui-electron\resources\ComfyUI\execution.py”, line 15, in
import comfy.model_management
[2025-09-25 10:30:21.976] [error]
File “C:\Users\toby\AppData\Local\Programs@comfyorgcomfyui-electron\resources\ComfyUI\comfy\model_management.py”, line 237, in

[2025-09-25 10:30:21.977] [error] total_vram = get_total_memory(get_torch_device()) / (1024 * 1024)

[2025-09-25 10:30:21.978] [error]
[2025-09-25 10:30:21.979] [error]
[2025-09-25 10:30:21.979] [error]
[2025-09-25 10:30:21.980] [error] ^^^^
[2025-09-25 10:30:21.981] [error] ^^^^^^^^^^^^^^
[2025-09-25 10:30:21.982] [error]
File “C:\Users\toby\AppData\Local\Programs@comfyorgcomfyui-electron\resources\ComfyUI\comfy\model_management.py”, line 187, in get_torch_device

[2025-09-25 10:30:21.982] [error] return torch.device(torch.cuda.current_device())

[2025-09-25 10:30:21.983] [error]
[2025-09-25 10:30:21.984] [error]
[2025-09-25 10:30:21.984] [error] ^^
[2025-09-25 10:30:21.985] [error] ^^^^^^^
[2025-09-25 10:30:21.985] [error] ^^^^^^^
[2025-09-25 10:30:21.986] [error] ^^^^^^^^^^^

[2025-09-25 10:30:21.987] [error] File “C:\Users\toby\Documents\ComfyUI.venv\Lib\site-packages\torch\cuda_init_.py”, line 1026, in current_device

[2025-09-25 10:30:21.988] [error] lazy_init()
File "C:\Users\toby\Documents\ComfyUI.venv\Lib\site-packages\torch\cuda_init
.py", line 372, in _lazy_init

[2025-09-25 10:30:21.988] [error] torch._C._cuda_init()

[2025-09-25 10:30:21.989] [error] RuntimeError: config[i] == get()->name() INTERNAL ASSERT FAILED at “C:\actions-runner\_work\pytorch\pytorch\pytorch\c10\cuda\CUDAAllocatorConfig.cpp”:253, please report a bug to PyTorch. Allocator backend parsed at runtime != allocator backend parsed at load time

It seemed to be an issue with KJNODES. The solution for me was to just fully uninstall Comfy UI, then manually delete it’s folder, then re-install from scratch. Then it all worked fine.