User Username not found in membership store does not exist

Question

Within our community server site, when I navigate to the UserList.aspx page, I get the following error every time: User Not Found, The user you requested cannot be found.

When I check the event log, I see asp.net warnings as follows:

Event Type: Warning
Event Source:   ASP.NET 2.0.50727.0
Event Category: Web Event 
Event ID:   1309
Date:       4/17/2013
Time:       9:39:43 AM
User:       N/A
Computer:   SV3369
Description:
Event code: 3005 
Event message: An unhandled exception has occurred. 
Event time: 4/17/2013 9:39:43 AM 
Event time (UTC): 4/17/2013 2:39:43 PM 
Event ID: f121eb3cd0a847b2a53972a09f802235 
Event sequence: 11116 
Event occurrence: 1072 
Event detail code: 0 

Application information: 
    Application domain: /LM/W3SVC/8022/ROOT-1-130105941980617500 
    Trust level: Full 
    Application Virtual Path: / 
    Application Path: C:\Inetpub\wwwroot\wisdomresearch.org\wwwroot\ 
    Machine name: SV3369 

Process information: 
    Process ID: 4148 
    Process name: w3wp.exe 
    Account name: NT AUTHORITY\NETWORK SERVICE 

Exception information: 
    Exception type: CSException 
    Exception message: User Username not found in membership store does not exist. 

Request information: 
    Request URL: http://wisdomresearch.org/themes/basic/Arete/UserList.aspx?interest=European+History 
    Request path: /themes/basic/Arete/UserList.aspx 
    User host address: 173.199.116.83 
    User:  
    Is authenticated: False 
    Authentication Type:  
    Thread account name: NT AUTHORITY\NETWORK SERVICE 

Thread information: 
    Thread ID: 8 
    Thread account name: NT AUTHORITY\NETWORK SERVICE 
    Is impersonating: False 
    Stack trace:    at CommunityServer.Users.AddMembershipDataToUser(UserSet users)
   at CommunityServer.Users.GetUsers(UserQuery query, Boolean cacheable)
   at Arete.Common.GetGlobalUsersTable()
   at PageBase.GetUsersTableFromCache()
   at Themes_basic_Arete_userlist.BindUsers()
   at Themes_basic_Arete_userlist.ExecuteSearch()
   at Themes_basic_Arete_userlist.Page_Load()
   at System.Web.Util.CalliHelper.ArglessFunctionCaller(IntPtr fp, Object o)
   at System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e)
   at System.Web.UI.Control.OnLoad(EventArgs e)
   at System.Web.UI.Control.LoadRecursive()
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

Also, I've seen this post, but I'm unsure of what I need to do if this is my problem.

Answer 1

First of all, I'm not familiar with community server site, although I used ASP.Net Membership extensively.

According to the SO link in your question, the problem is users are missing in cs_Users table (or might be other table).

1 - You need to find those orphaned rows. Something like this -

SELECT * FROM aspnet_Users WHERE UserId NOT IN (SELECT UserId FROM cs_Users)

2 - Then you either need to delete them or do something.