Can you try the steps mentioned in this below thread once again and let us know if that helps?
If the issue persists, would you install our Canary build to see if it opens as expected?
- Postman Canary – Postman Canary: For Mac, Windows, & Linux
The canary build will be installed an entirely separate app/directory – if it works as expected, feel free to continue using it or to uninstall it entirely.