Anaconda Prompt执行conda update触发SyntaxError问题求助

Hey there, let's work through this issue you're having—since you've got a ton of custom packages installed, reinstalling Anaconda is definitely not the way to go. Let's break down what's happening and how to fix it:

What's Causing the Syntax Error? #

That SyntaxError in _base.py is a dead giveaway: the line raise exception_type, self._exception, self._traceback is Python 2 syntax, but you're running Python 3.x in your Anaconda environment. This means your system is accidentally using a Python 2 interpreter or a corrupted Python 3 module when trying to run conda—most likely because your PATH modification for Graphviz messed up the priority of Anaconda's Python executable.

Step-by-Step Fixes #

1. Fix Your PATH Environment Variable

First, let's make sure Anaconda's Python is the first one your system finds:

• Right-click "This PC" → Properties → Advanced System Settings → Environment Variables
• Under System Variables, find the PATH entry and edit it
• Move these two paths to the top of the list (replace NSing with your actual username if needed):
  • C:\Users\NSing\AppData\Local\Continuum\anaconda3
  • C:\Users\NSing\AppData\Local\Continuum\anaconda3\Scripts
• Click OK to save, then close and reopen your command prompt to apply changes

2. Reinstall the Corrupted concurrent.futures Module

If the PATH fix doesn't work, the concurrent.futures module might be damaged. Reinstall it using Anaconda's own pip to avoid version mismatches:

(base) C:\Users\NSing> python -m pip install --force-reinstall futures

Make sure you're in the base conda environment when running this.

3. Force-Reinstall Conda Itself

If conda is still throwing errors, repair the conda installation directly:

(base) C:\Users\NSing> conda install --force-reinstall conda

If this command fails too, try running it with administrator privileges—sometimes file permissions can cause issues with overwriting core conda files.

4. Verify Which Python Your System is Using

To double-check the PATH fix worked, run this in your command prompt:

where python

The first path listed should be C:\Users\NSing\AppData\Local\Continuum\anaconda3\python.exe. If not, go back and adjust your PATH again.

Once you've worked through these steps, try running conda update --all again, then launch Anaconda Navigator and Spyder—they should start up normally without needing a full reinstall.

内容的提问来源于stack exchange，提问作者Nick