A few weeks ago, I suddenly became unable to download PNPM packages, receiving the following warning for all the packages I attempted to download:

GET https://registry.npmjs.org/<package> error (UNABLE_TO_GET_ISSUER_CERT_LOCALLY). Will retry in 10 seconds. 2 retries left.

After two retries, they eventually all failed. I initially thought this was a PNPM bug, as visiting https://registry.npmjs.org in Safari worked and showed a valid root certificate. However, running Python scripts that use urllib now fails with this error:

urllib.error.URLError: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:997)

This leads me to believe that the problem is system-level, since it is occurring in multiple completely different environments. The issue also affects terminals launched in 3rd-party apps, such as VSCode, but doesn't seem to affect other parts of those apps, or indeed any other apps at all. The solutions I've found online are mostly specific to a single tool (PNPM, urllib, etc), and involve disabling or working around SSL instead of actually solving the problem, which I don't want to do because of the security implications.

What I've Tried

  • Reinstalling macOS (without erasing it).
  • Checking my root certificates in Keychain Access (all are valid and none have expired).
  • Ensuring that I am not behind a proxy (to my knowledge)
  • Giving Terminal full disk access in case it's somehow being denied read access to the certificates


M1 MacBook Air running macOS Monterey 12.5.1

  • Update: This issue doesn't seem to affect all packages: cURL works fine Sep 4, 2022 at 14:40

1 Answer 1


After doing some troubleshooting, I noticed that the problem only occurred in packages installed in Homebrew. I reinstalled Homebrew, and all is well.

A tip for reinstalling Homebrew is that you can use brew bundle dump to dump a Brewfile bundle of all your packages in the current directory, then use brew bundle install to install them all again once Homebrew has been reinstalled. I'd also recommend deleting /opt/homebrew as well as running their uninstallation script.

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