Pop-up Blocker Settings requires you to add the URL Prefix everytime ?

Published: Sep 02, 2005
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When you attempt to add a domain name to the Pop-up Blocker Allow list in Windows XP Service Pack 2, you may receive the following error message:

You have entered an invalid domain. Domains must be
in the Internet zone and must use the HTTP or HTTPS protocol.

Examples of valid domains:



This happens if the DefaultPrefix registry value is missing, and when you try to add a domain name without specifying the prefix ( http://, https://  etc). To resolve the problem, correct the default prefix value using the following steps:

Click Start, Run and type REGEDIT

Navigate to the following location:

HKEY_LOCAL_MACHINE \ SOFTWARE \ Microsoft \ Windows \ CurrentVersion \ URL \ DefaultPrefix

In the right-pane, double-click (default) and set it to http://