Removing all your locally stored challenges will solve many problems related to the browser crashing on FreeCodeCamp

In Chrome:

• On freecodecamp open your console
  • Windows: Ctrl + Shift + J
  • Mac OS: Cmd + Opt + J
• Go to resources tab(chrome).
  • There click on the "Local Storage" link in the nav bar on the right.
• Delete all the entries on the right side, or run this command in your browser's console to clear all entries from your localStorage: localStorage.clear();
• See if this solves your issue

Alternatively, if you are having issues with a specific challenge freezing your browser, find the name of that challenge in local storage and delete just that one.