Hey there! Sorry to hear you're stuck after updating your GitHub username and reconfiguring Git in GitHub Desktop. Since you didn’t include the specific error message yet, let me walk you through some common fixes and checks that usually resolve most post-username-update issues:

• Double-check your global Git configs
  Don’t rely solely on GitHub Desktop—open a terminal (Command Prompt, Terminal app, etc.) and run these commands to confirm your username/email match your new GitHub account:

  git config --global user.name
  git config --global user.email
  

  If they show your old details, update them with:

  git config --global user.name "Your New GitHub Username"
  git config --global user.email "your-linked-github-email@example.com"
  

• Check repository-specific config overrides
  Some repos have local settings that take priority over global ones. Navigate to your project folder in terminal and run:

  git config user.name
  git config user.email
  

  If you see your old username here, update it with the --local flag:

  git config --local user.name "Your New GitHub Username"
  

• Fix outdated remote repo URLs
  Your repo might still be pointing to the old username’s remote address. Verify this with:

  git remote -v
  

  If you see https://github.com/OLD-USERNAME/your-repo.git, update it to your new username:

  git remote set-url origin https://github.com/NEW-USERNAME/your-repo.git
  

• Refresh GitHub Desktop authentication
  The app often caches old auth data. Go to File > Options > Accounts, remove your old account entry, re-add your new GitHub account, then restart the app.
• Clear system credential caches
  Your computer might be storing old GitHub login credentials. On Windows, open Credential Manager > Windows Credentials and delete any GitHub-related entries. On macOS, open Keychain Access, search for "GitHub", and delete outdated login items.

If none of these steps resolve the issue, please share the exact error message you’re seeing (copy-paste the full text from terminal pop-ups or GitHub Desktop alerts)—that will help narrow down the exact problem!

内容的提问来源于stack exchange，提问作者circl