I get a message that I didn't type a valid date

Dates must be in the correct format such as MM/DD/YYYY or M/D/YY. Note that the actual date format may vary depending upon the locale specified for the site on the Regional Settings page in Site Administration.

I typed a Web address in a text field and, when I view the item, only part of the Web address is a hyperlink

If the Web address includes a space, type %20 for the space. For example, http://example.com/my%20site

I typed a mailto: address in a text field, and when I view the item, it isn't an active hyperlink

All mailto: addresses must be in lowercase letters. For example:

mailto:someone@example.com

I can't edit an item with a date column

You can't edit a list item that has a date older than 1900 or greater than 8900. To resolve this problem, delete the item and add it with a date between the year 1900 and 8900.