If you are receiving the error code 8100030d when signing into Windows Live Messenger, do the following:

1. Determine what version of Messenger is installed on the computer. The latest version of Messenger is 14.0.8064.206. Upgrade Messenger to the latest version from http://download.live.com if required.

Click here to determine the most recent versions of Messenger for each operating system. If you are not running the latest version for your operating system, please install the most updated version.

2. Delete the cache files for Messenger. Follow the steps below based on which version of Operating System that you are using:

Enable Hidden files and Folders:

Windows XP :

1. Click on Start – My Computer (double click on it)
2. On the Tools menu, Click on Folder Options. 
3. On the View tab, locate Advanced settings and then follow these steps :
    3.a Click Show Hidden Files and Folders
    3.b Clear the Hide protected operating system files check box.
    3.c  Clear Hide file extensions for known file types check box.
4. Click OK and close the Window.

Windows Vista:

1. Click on Start – My Computer (double click on it)
2. In the Explore window, click Organize
3. Choose Folder and Search Options
4. In the Folder options window, click on view tab
5. Select the option “Show Hidden Files and Folders” click Ok

Delete Windows Live Contacts Folders in Windows Live Messenger:

1. Click on Start – Double click on My computer

2. Browse to the location:

(In Windows Vista, C:\Users\<Windows Logon name>\App Data\Local\Microsoft).
(In Windows XP, go to C:\Documents and Settings\<Windows logon name>\Local Settings\Application Data\Microsoft)

Note: Windows Logon name is the logon name that you use to sign in to windows. Your Messenger email address is the address that you use to sign in to Messenger. 

3. Look for Windows Live Contacts folder and delete the entire folder.

Note: Please ensure to exit Messenger even from the task manager before deleting this folder.

4. Try to Sign into Windows Live Messenger again.

The following additional steps to configure the AVG 8.0 software’s Web Shield component also helps in addressing the error.

1. Open the AVG User Interface.
2. Double-click on the Web Shield component.
3. Switch on the Instant Messaging tab.
4. Uncheck the Instant Messaging protection option.
5. Confirm changes by clicking the Save Changes button.

Note: In case the issue persists please try to deactivate the Web Shield component completely. If it’s still not possible to connect to the Windows Live Messenger service and the AVG Firewall component is installed in the AVG program, please check its settings. Try to run the Configuration Wizard to configure the firewall component properly. For illustrated instructions, please refer to this blog post:

http://messenger-support.spaces.live.com/blog/cns!8B3F39C76A8B853F!14004.entry

The above steps do not apply for free AVG 8.0 software users.