http://support.microsoft.com/kb/947215/en-us

SYMPTOMS
When you log on to a Windows Vista-based computer by using a temporary profile,...

When you log on to a Windows Vista-based computer by using a temporary profile, you receive the following error message:
The User Profile Service failed the logon. User profile cannot be loaded.
This error may occur if the "Do not logon users with temporary profiles" Group Policy setting is configured.

CAUSE
This issue may occur if the user profile was manually deleted by using the comma...

This issue may occur if the user profile was manually deleted by using the command prompt or by using Windows Explorer. A profile that is manually deleted does not remove the security identifier (SID) from the profile list in the registry.

If the SID is present, Windows will try to load the profile by using the ProfileImagePath that points to a nonexistent path. Therefore, the profile cannot be loaded.

RESOLUTION
Important This section, method, or task contains steps that tell you how to modi...

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756  ([url]http://support.microsoft.com/kb/322756/[/url] ) How to back up and restore the registry in Windows


To resolve this issue, follow these steps:
  1. Delete the profile by using the Computer Properties dialog box. To do this, follow these steps:
    1. Click Start, right-click Computer, and then click Properties.
    2. Click Change settings.
    3. In the System Properties dialog box, click the Advanced tab.
    4. Under User Profiles, click Settings.
    5. In the User Profiles dialog box, select the profile that you want to delete, click Delete, and then click OK.
  2. Click Start
    Collapse this imageExpand this image
    the
    , type regedit in the Start search box, and then press ENTER.
  3. Locate and then expand the following registry subkey:
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList
  4. Right-click the SID that you want to remove, and then click Delete.
  5. Log on to the computer and create a new profile.