Deleting Comments Causes Access Denied Message

Problem:

When attempting to delete comments in a virtualized Community Server instance, an Access Denied error sometimes occurs.

Cause:

If multiple application names are used for a single virtualized installation of Community Server, a cache collision can occur between users with the same username in multiple membership sets. This issue is most likely to occur with the anonymous user (username: "Anonymous") but can also occur with registered users. 

The Access Denied error occurs when one site caches a similarly-named user and another site retrieves this user from the cache and assigns it as the author of a post (or comment). The post's author then does not exist as a user of the site, resulting in the Access Denied error when retrieving the post during deletion.

Solution:

Community Server 2007.1 included an update to the caching logic used for membership data to prevent cache collisions. After Community Server 2007.1 was installed, the following SQL script should have been executed against your existing Community Server database to correct invalid post authors.

update cs_Posts
set UserID = u2.UserID
from cs_Posts
inner join cs_Sections s on cs_Posts.SectionID = s.SectionID
inner join cs_vw_Users_FullUser u1 on cs_Posts.UserID = u1.UserID
inner join cs_vw_Users_FullUser u2 on u1.Username = u2.Username and s.SettingsID = u2.SettingsID
where u1.SettingsID <> s.SettingsID