- You attempt to specify a domain user in any People Picker field within SharePoint 2007 / 3.0
- AD domain users have resolved before.
- The application service is running under a local machine account
- The username will not resolve. Instead you get the squiggly red underline.
- Workaround: Change the Service Account to a domain user account
I do not know why a local account would exhibit this behaviour nor why this would randomly stop working. After changing to a domain account temporarily you can change back to a local account, but the issue will occur again. My guess is that it's environment specific, such as a temporary loss of AD connectivity, which would explain the intermittant occurances.