Ok so you are using uva and still uv is getting confused and trying to use your system's Python 3.13.2, even when you ask for 3.9.21. This happens because uv needs a clear path to the specific Python version you want for your project.

This is usually the simplest and best way to tell uv exactly what to use for a project.

1. Go into your project folder:

\>>>mkdir sandboxcd sandbox

2. Tell uv to use Python 3.9.21 for this folder:

\>>>uv python pin 3.9.21

If you don't have 3.9.21 installed yet via uv, it might ask you to install it.

3. Now, create and sync your project:

\>>>uv init --package

\>>>uv sync

uv will now automatically use the pinned 3.9.21.