A while ago a customer had problems with his User Profile Service. Since the problems may exist on other SharePoint farms as well, I want to share the solutions I found.

1. “Could not load user profile.”
   This exception occurs, if you click on a MySite link.
   
   To get rid of the problem, I had to associate the User Profile Service Application to the Webapplication, where the MySite-Host is running.
2. The User Profile Import does not run
   Trying to import user profiles from the Active Directory, I clicked on the link “Start Profile Synchronization” in the User Profile Service Application settings pages. Nothing happened. Hmm. The SharePoint logs showed an exception after I clicked on the link:
   
   UserProfileApplication.GetStageStatus: Unexpected exception: System.Management.ManagementException: Generic failure 
   
   The eventlog had a new entry, too:
   Log Name:      Application
   Source:        Microsoft-SharePoint Products-SharePoint Foundation
   Date:          22.10.2010 09:28:56
   Event ID:      6398
   Task Category: Timer
   Level:         Critical
   Keywords:     
   User:          domain\user
   Computer:      server.domain.tld
   Description:
   The Execute method of job definition Microsoft.Office.Server.UserProfiles.UserProfileImportJob (ID 476df0f2-0f5d-34ce-afbe-9fe6fd1584e3) threw an exception. More information is included below. Generic failure
   
   To get rid of this exception, I had to grant read permissions to the “Network Service” and “System” accounts to this folder: C:\Program Files\Microsoft Office Servers\14.0
3. Granting permission from the previous step, also solved this problem in the eventlog:
   

UserProfileApplication.SynchronizeMIIS: Failed to configure MOSS initial MAs, will attempt during next rerun. Exception: System.Management.ManagementException: Generic failure