SharePoint Designer 2007 Error: The folder ‘http://servername’ isn’t accessible. The folder may be located in an unavailable location, protected with a password, or the filename contains a / or \.

Wow. What a great error message! Ok, so we get the fact that it is not accessible, since we cannot get to it. This wild goose chase has had me running in circles for a while now. I checked everything. EVERYTHING! Web application policies, permissions, client integration settings, files in the SharePoint root, web.config settings, site definition configurations, group policy settings, and on and on and on… nothing. Every reference I could find of this error either had to do with Forms Based Authentication, and other miscellaneous issues.

Finally, I decided to check the hosts file, located in c:\Windows\system32\drivers\etc\. And there lied the resolution to this issue. Hosts file entries for the server name. When this server was initially being built, in order to get going on a few things, entries were added into the hosts file to masquerade as the future DNS names for the server. However, this was also the cause of the issue. By removing those entries, I could now open the site with SharePoint Designer 2007.

Reason for the post? A glimmer of hope for someone who comes across the same issue in the future.