DLL Load failed error

Has anyone had any experience with a “ImportError: DLL load failed while importing _arpack: The specified procedure could not be found.”?

The background is originally I installed Python 3.10 on my windows desktop computer and was using that quite happily although I could not install Cartopy.

I found that by installing Anaconda I could get python 3.9 installed with Cartopy and did that. After doing so, I found 3.10 was still reliable by 3.9 was not. Presumably the two versions weren’t happy together.

I installed anaconda and python 3.9 on my new laptop and it works fine, so I decided to unistall 3.10 on my desktop and concentrate on 3.9 with both Obspy and cartopy. Problems got worse, so I checked all PATH environment variable and got rid of references to the python 3.10 locations.

Eventually I uninstalled anaconda and reinstalled and set up Cartopy and Obspy again, but this error persists. It happens on all my reports.

The line in my program/module seems to be the “from obspy.signal import filter”. All the calls after that appear to be in modules outside my program.

Here’s a copy of the console output:

I appreciate any help anyone can suggest. I haven’t yet sat down with my laptop to check it still works as it did last week, and check off versions of the various modules. I suspect it is something else as Anaconda is supposed to manage compatibility between the modules.


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For future reference I’ve solved this.

I found an entry in PYTHONPATH environment variable which was left over from my original PY3.10 installation that I’d missed when uninstalling. That didn’t fix the problem itself but I suspect messed up the Scipy install.

I then uninstalled Cartopy, Obspy and Scipy from the base environment in Anaconda, and then reinstalled Scipy only.

I then created a new environment for Obspy and Cartopy. This appears to be successful.



Thank you for posting the solution to the problem sheeny.

In full honesty, it’s the first time I saw a DLL issue related to a Python package, but my suggestion would have been something along the line of “try to create a new environment and see if it happens again”.

Well done!

As you know I’m relatively new to Python, but been programming in other languages on and off for about 45 years, so I know just enough to be dangerous! lol!