As promised, today we will be talking about how to fix error 8100030d when trying to sign in to Windows Live Messenger.  The solution is to empty your Contacts cache.  The single steps depend on your Windows version.

If you are using Windows XP, try the following.

  • Are you using the latest version of Messenger?  If not, consider updating at http://download.live.com/messenger.
  • Exit Messenger.
  • Show hidden folders in Windows Explorer.
  • Click Start, My Computer.
  • Open the Tools menu, and choose Folder options…
  • Switch to the View tab.
  • Check the option Show all files and folders.
  • Uncheck the option Hide file extensions for known file types.
  • Click OK to close the dialog.
  • Now empty your Contacts cache.
    • Browse to C:\Documents and Settings\<User name>\Contacts\<Windows Live ID>.
    • Delete all files in this folder.  Do NOT delete the folder itself, only its contents.
    • Now browse to C:\Documents and Settings\<User name>\Local Settings\Application Data\Microsoft\Windows Live Contacts\<Windows Live ID>.
    • Delete the two subfolders Real and Shadow inside this folder.
  • Finally, retry to sign in to Messenger.

    • In case your operating system is Windows Vista or Windows 7, the following steps should help.

    • Are you using the latest version of Messenger?  If not, consider updating at http://download.live.com/messenger.
    • Exit Messenger.
    • Show hidden files in Windows Explorer.
    • Click Start, Computer.
    • Open the Organize dropdown, and choose Folder and Search options…
    • Switch to the View tab.
    • Check the option Show all files and folders.
    • Uncheck the option Hide file extensions for known file types.
    • Click OK to close the dialog.
  • Now empty your Contacts cache.
    • Browse to C:\Users\<User name>\Contacts\<Windows Live ID>.
    • Delete all files in this folder.  Do NOT delete the folder itself, only its contents.
    • Now browse to C:\Users\<User name>\AppData\Local\Microsoft\Windows Live Contacts\<Windows Live ID>.
    • Delete the two subfolders Real and Shadow inside this folder.
  • Finally, retry to sign in to Messenger.

    • Note: The <User name> is your Windows user name; the <Windows Live ID> is the e-mail address you use to sign in to Messenger.

    This fixed your issue?  Wonderful.
    It didn’t?  Please contact the Windows Live support at http://support.live.com/ .

    Source:
    http://messengermaximal.spaces.live.com/Blog/cns!40F43EC9BA81D814!5903.entry
    http://messenger-support.spaces.live.com/blog/cns!8B3F39C76A8B853F!13937.entry