SharePoint TIP: resolving user prompted to log into SharePoint website

Level: Beginner

Problem

A not infrequent problem that your users may encounter now and then is all of a sudden being prompted to log into a corporate intranet SharePoint website, when he or she didn't have to before.  These kinds of problems are not usually SharePoint-related, since SharePoint doesn't actually do any authentication.  However, such an issue may get routed to you inadvertently since it involves a "SharePoint" website.  While the experienced Active Directory administrator may quickly understand the underlying problem, this kind of problem may puzzle the beginning SharePoint administrator.  Here are some simple, routine steps you can have the user take before routing the issue onwards to the AD administrators.  

First, verify Windows Integrated Authentication (IWA) has been enabled for the browser.  To do this for Chrome and Internet Explorer, have the user:

1. Bring up Control Panel.
2. Double-click on Internet Options.
3. Select the Advanced tab
4. Scroll down to the Security group (about three fourths down)
5. Look for the Enable Integrated Windows Authentication setting
6. Ensure this setting is enabled.
7. Click OK.
8. Restart the machine.

To do this for Firefox, have the user:

1. Launch Firefox
2. In the address box, enter about:config.
3. In the Search box, enter network.automatic.
4. Enter the URLs, separated by commas, of the sites.
5. Click OK.
6. Restart Firefox.

Second, if these settings are not accessible by the user, have the user launch a new DOS shell (doesn't need to be elevated), and then enter the following and press ENTER:

gpupdate /force

These simple steps can resolve most instances of the login prompt problem when it appears.  If these steps don't resolve this problem, then elevate to the AD administrators.

References

• Integrated Windows Authentication
• Internet Explorer May Prompt You for a Password
• AD FS Troubleshooting - Integrated Windows Authentication
• Google Chrome Help
• Enable Integrated Windows Authentication (IWA) in Mozilla Firefox

Notes

• Google Chrome doesn't have its own Network Settings control panel, but uses the same one as for the Windows operating system, which is the one used by Internet Explorer.
• The problem discussed here will likely be obvious to systems administrators but may present a puzzle to SharePoint administrators unfamiliar with or new to concepts such as "GPO", Internet Explorer security zones and single sign-on and who may have only a general understanding of Active Directory.  
• Sometimes, a user may raise the issue of being prompted to log into a SharePoint website, and that issue may be routed to you by your helpdesk because it involves a "SharePoint site".  It really isn't a SharePoint issue and in fact doesn't really involve SharePoint at all, but you may still want to resolve it just to help that user quickly and efficiently.
• The login prompt problem can occur for a variety of reasons.  Perhaps the user has been away for some time, leaving his or her machine off and so it failed to get GPO updates.  Perhaps the user installed a new application that disabled authentication credential pass-through.  Or maybe the user disabled the setting so as to be able to login under a different account at some other website and then forgot to re-enable it.