To prevent Internet Explorer from prompting users to save User Names and Passwords, you can enable the Do not allow AutoComplete to save passwords Group Policy at User Configuration \ Administrative Templates \ Windows Components \ Internet Explorer.
When you enable this policy, it disables the automatic completion of user names and passwords in forms on Web pages, and prevents users from being prompted to save passwords. The User Names and Passwords on Forms and Prompt Me to Save Passwords check boxes are dimmed on the AutoComplete dialog of the Internet Options / Content tab.
NOTE: See Disable the Content page policy.
NOTE: Enabling the Do not allow AutoComplete to save passwords policy sets the FormSuggest Passwords Value Name, a REG_DWORD data type, to 1, at HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Control Panel.
Related tips:
How can I make Internet Explorer forget all the passwords I had it previously remembered?How can I get Internet Explorer to ask me to remember passwords again?
How do I use AutoComplete in Internet Explorer 5.x?
