This article was previously published under Q250449
IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:
256986 Description of the Microsoft Windows Registry
When you try to change the short or long date style settings in the Regional Settings tool in Control Panel, you may receive the following error message:
One or more of the characters you typed in this field are invalid. Try typing different characters.
After you click OK to dismiss this error message, and then click OK to quit the Regional Settings tool, changes you made to the date settings are not retained.
This issue can occur if the following registry key is missing:
WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.
To resolve this issue, add the following registry key and its associated string values, and then restart your computer: