-
Notifications
You must be signed in to change notification settings - Fork 13.8k
Replies: 2 comments · 7 replies
-
|
I happened to run across a pull request to fix this issue (that's not merged yet). |
Beta Was this translation helpful? Give feedback.
All reactions
-
|
This did not fix it for me on a fresh installation. Same error as before - identical to yours. |
Beta Was this translation helpful? Give feedback.
All reactions
-
|
Patch appears to have worked fine but I'm still getting an error: Script log: =========== RESTART: /Users/USERNAME/Downloads/patch_comfy_mps_fp8.py =========== Done. You can launch ComfyUI. Here is the job run log: TypeError: Trying to convert Float8_e4m3fn to the MPS backend but it does not have support for that dtype. ComfyUI Error ReportError Details
Stack TraceSystem Information
Devices
LogsAttached WorkflowPlease make sure that workflow does not contain any sensitive information such as API keys or passwords. Additional Context(Please add any additional context or steps to reproduce the error here) |
Beta Was this translation helpful? Give feedback.
All reactions
-
|
I prepared a more complete version of the patcher. This version no longer depends on my local username or one fixed installation path. It searches for the relevant ComfyUI and comfy-kitchen files automatically, verifies that they contain the expected functions, creates backups, applies the patch only where needed, and runs a Python syntax check after patching. It now covers the broader FP8/MPS fallback surface:
This is still only a local workaround, not an official upstream fix, but it should be more useful for different Apple Silicon / macOS ComfyUI installations. |
Beta Was this translation helpful? Give feedback.
All reactions
-
Could you share the location please? I was trying to find it. The script (latest) runs, but fails to find the quantization bit |
Beta Was this translation helpful? Give feedback.
All reactions
-
I poked around in terminal and google until I found it but yours might be slightly different so definitely validate it before running |
Beta Was this translation helpful? Give feedback.
All reactions
-
@vSnake87 i'm using '--force-fp16 --fp32-vae --use-pytorch-cross-attention --highvram' with 'PYTORCH_MPS_HIGH_WATERMARK_RATIO' set to 0.0 for my M1 Max 64GB. but not sure because i get different info from everywhere i've been searching |
Beta Was this translation helpful? Give feedback.
Uh oh!
There was an error while loading. Please reload this page.
Uh oh!
There was an error while loading. Please reload this page.
-
Working Apple Silicon / macOS workaround for ComfyUI FP8 MPS crash after updates
I’m sharing a working local workaround for Apple Silicon users running ComfyUI on macOS with the MPS backend and hitting this error:
TypeError: Trying to convert Float8_e4m3fn to the MPS backend but it does not have support for that dtype.
In my case, the issue returned after a ComfyUI update because the files I had previously patched were overwritten again.
What fixed it for me was patching two separate locations:
ComfyUI core
/Applications/ComfyUI.app/Contents/Resources/ComfyUI/comfy/float.py
comfy_kitchen inside the local ComfyUI virtual environment
~/ComfyUI/.venv/lib/python3.12/site-packages/comfy_kitchen/backends/eager/quantization.py
Why both patches were necessary in my setup:
stochastic_rounding(...)comfy_kitchenindequantize_per_tensor_fp8(...)The logic of the workaround is simple:
After patching both files, the official LTX 2.3 workflow worked again correctly on my Apple Silicon Mac with MPS enabled.
More importantly, in my case this was not limited to a single workflow. After applying both patches, all FP8 models I personally tested in ComfyUI were able to launch and run without triggering the Float8_e4m3fn MPS backend crash. I cannot guarantee identical results for every environment, but on my machine this consistently resolved the FP8-on-MPS failure path.
Because updates can overwrite the modified files again, I wrapped the workaround into a small Python patcher script so I can re-apply it quickly after future ComfyUI updates.
Important notes:
~/ComfyUI/.venv/...Sanitized patcher script:
How to use:
Save the script as something like patch_comfy_mps_fp8.py
Close ComfyUI
Run the script with Python
Re-open ComfyUI
Re-run your FP8 workflow
If anyone else on Apple Silicon tests this successfully on additional FP8 models or workflows, it would be useful to compare results.
patch_comfy_mps_fp8.py
Beta Was this translation helpful? Give feedback.
All reactions