Comfy-Org
"Neither python -m pip nor uv are available" error comes on starting ComfyUI with ComfyUI-Manager
OS: Nobara Linux 42 KDE ComfyUI: v0.3.64 ComfyUI-Manager: v3.37
I was using ComfyUI and ComfyUI-Manager using Python v3.13 venv until yesterday. Today I deleted that venv folder and created a new one with Python v3.12. Then I reinstalled ComfyUI pip requirements and tried to start the server using the command python main.py in the activated venv. But I got this error:
venv ❯ python main.py
[START] Security scan
[ComfyUI-Manager] Neither python -m pip nor uv are available. Cannot proceed with package operations.
Failed to execute startup-script: /home/username/Applications/ComfyUI/custom_nodes/comfyui-manager/prestartup_script.py / Neither pip nor uv are available for package management
pip is installed and listed as a module when I check pip list.
See the output of this command:
venv ❯ python -c "import subprocess; print(subprocess.run(['python', '-m', 'pip', '--version'], capture_output=True, text=True))"
CompletedProcess(args=['python', '-m', 'pip', '--version'], returncode=0, stdout='pip 25.2 from /home/username/Applications/ComfyUI/venv/lib64/python3.12/site-packages/pip (python 3.12)\n', stderr='')
Doesn't this mean that pip is properly installed? Then why is that error showing up?
Not sure whether this is ideal, but what I did to solve this was to set use_uv = False in the ComfyUI-Manager file: /home/username/Applications/ComfyUI/user/default/ComfyUI-Manager/config.ini. It was set to True there by default.
I installed 25H2 and I thought this error was due to the new system or a bug in 25H2, I installed other versions of Python several times and the thing keeps happening, comfyui won't start and the same error always appears
[ComfyUI-Manager] python -m pip not available. Falling back to uv. [ComfyUI-Manager] Neither python -m pip nor uv are available. Cannot proceed with package operations. Failed to execute startup-script: E:\ComfyUI_windows_portable_nvidia\ComfyUI_windows_portable\ComfyUI\custom_nodes\comfyui-manager\prestartup_script.py / Neither pip nor uv are available for package management
Then I went back to 24H2, first start and everything is fine (too long to open but I was happy that the program started), I install the manager and the start is normal, I even manage to make some pictures! This morning I start the program again and the same error repeats, I really have no idea what else to do, I tried everything I could think of and what I found on the internet
@DarthDiabolik Did you try this?
Not sure whether this is ideal, but what I did to solve this was to set use_uv = False in the ComfyUI-Manager file: /home/username/Applications/ComfyUI/user/default/ComfyUI-Manager/config.ini. It was set to True there by default.
First of all, thank you for your help and answer, secondly (I know it sounds stupid) I'm glad I'm not alone with this problem, because after a few days of searching this is the first time I've found someone with a similar problem (at one point I even thought that maybe my GPU was causing this problem)! Unfortunately, your solution didn't help me, in my ini. file use_uv = was already set to False, I changed it to True and that didn't help either, the problem still exists! In any case, thank you, if I find a solution I'll let you know
First of all, thank you for your help and answer, secondly (I know it sounds stupid) I'm glad I'm not alone with this problem, because after a few days of searching this is the first time I've found someone with a similar problem (at one point I even thought that maybe my GPU was causing this problem)! Unfortunately, your solution didn't help me, in my ini. file use_uv = was already set to False, I changed it to True and that didn't help either, the problem still exists! In any case, thank you, if I find a solution I'll let you know
I also attempted the suggested fix running on a portable windows version of comfy. No luck. Proably not much help, but I ended up setting up a linux mint partition and it solved the issue. Can really recommend switching. No more headaches with dependencies.
I also attempted the suggested fix running on a portable windows version of comfy. No luck. Proably not much help, but I ended up setting up a linux mint partition and it solved the issue. Can really recommend switching. No more headaches with dependencies.
I used Zorin OS which is also fantastic but I had some problems with Photoshop and with some other programs and I returned to Windows again two years ago , since nothing of programs binds me to windows anymore there is a big possibility that I will soon switch again to either Zorin or Mint ! Otherwise the problem is definitely in the manager and probably also in the ini file, since I changed this suggested option, I returned to the False option again and Comfyui started and still shows that it is not reading pip and that it has switched to uv ,Honestly, for the last 6-7 months I've been afraid to update ComfyUI or Manager because I have some problems every time.
Have you installed the requirements of ComfyUI-Manager? I have just fixed the error by:
pip install -r path-to-your-comfyui-installed-location/custom_nodes/ComfyUI-Manager/requirements.txt
Hope this help.
