marimo uv sandbox crashes Windows 11 when uv run marimo edit

[nplevris]

Describe the bug

Command that crashes: uv run marimo edit test.py
Windows 11 environment crashes Rebooting device.

This was reproduced with python versions 3.12 & 3.13

Note that uv run python -c ... works fine

Will you submit a PR?

• Yes #6670

Environment

- Windows 11 build
- Python versions tested (3.12 & 3.13)
- uv version (0.8.22)

Code to reproduce

No response

[mscolnick]

@nplevris any more details you can provide? that seems like a pretty bad bug, but no one else can reproduce this.

what version are you on? you can check with uv run marimo env

[nplevris]

Here are the environment details for uv & marimo:

{
"marimo": "0.16.5",
"editable": false,
"location": "C:/Users/nplev/.TalkPython/Lib/site-packages/marimo",
"OS": "Windows",
"OS Version": "11",
"Processor": "AMD64 Family 25 Model 68 Stepping 1, AuthenticAMD",
"Python Version": "3.12.11",
"Locale": "el_GR",
"Binaries": {
"Browser": "140.0.7339.208",
"Node": "--"
},
"Dependencies": {
"click": "8.3.0",
"docutils": "0.22.2",
"itsdangerous": "2.2.0",
"jedi": "0.19.2",
"markdown": "3.9",
"narwhals": "2.6.0",
"packaging": "25.0",
"psutil": "7.1.0",
"pygments": "2.19.2",
"pymdown-extensions": "10.16.1",
"pyyaml": "6.0.3",
"starlette": "0.48.0",
"tomlkit": "0.13.3",
"typing-extensions": "4.15.0",
"uvicorn": "0.35.0",
"websockets": "15.0.1"
},
"Optional Dependencies": {
"openai": "2.1.0",
"pandas": "2.3.3",
"loro": "1.8.1"
},
"Experimental Flags": {}
}

[nplevris]

Everything works as expected on a MacOS environment. So this issue is highly Windows related.

[mscolnick]

hey @nplevris, we are unable to repro on windows ourself. please let us know if you can get us any more info (stack traces, certain repro setups)

[nplevris]

Hi @mscolnick , I'm uploading an internal uv trace with the -vvv . Problem reproduced with the command:
uv -vvv run marimo edit --sandbox my1stmarimo.py

uv_trace.log

[mscolnick]

I see errors like:

--- Logging error ---
Traceback (most recent call last):
    self.rotate(self.baseFilename, dfn)
  File "C:\Users\nplev\AppData\Roaming\uv\python\cpython-3.11.13-windows-x86_64-none\Lib\logging\handlers.py", line 115, in rotate
    os.rename(source, dest)
PermissionError: [WinError 32] The process cannot access the file because it is being used by another process: 'C:\\Users\\nplev\\.cache\\marimo\\logs\\marimo.log' -> 'C:\\Users\\nplev\\.cache\\marimo\\logs\\marimo.log.2025-10-04'

I will look into handling these errors