UGTS Document #28 - Last Modified: 8/29/2015 3:23 PM
Windows User Profile problems

Sometimes Windows will have a temporary problem loading a user's profile, and when this happens, you may get the error message 'The User Profile Service failed the logon. User profile cannot be loaded'.

Normally, the path to a user's profile directory in a key named by the SID of the user in the ProfileImagePath value under the key:

HKLM\Software\Microsoft\Windows NT\CurrentVersion\ProfileList

However, if the profile cannot be loaded for whatever reason, Windows will rename the [SID] key to '[SID].bak', will change turn on bit 0x8000 on the State value to indicate that the profile was backed up, and will create a new SID key pointing to a temporary directory. The full list of State bits is defined in profile.h:

  PROFILE_MANDATORY      0x00000001
  PROFILE_USE_CACHE      0x00000002
  PROFILE_NEW_LOCAL      0x00000004
  PROFILE_NEW_CENTRAL    0x00000008
  PROFILE_GUEST_USER     0x00000080
  PROFILE_ADMIN_USER     0x00000100
  DEFAULT_NET_READY      0x00000200
  PROFILE_SLOW_LINK      0x00000400
  PROFILE_THIS_IS_BAK    0x00008000

(Bit 0x40 is not used because NT4 uses this for syncapps. Bit 0x1000 was used briefly in 2009/10, but was not used after that, and so it was also skipped.)

Sometimes all that is needed to restore the profile that windows has marked corrupt is to update the registry. First restart the machine. Then remove the 0x8000 bit from the State value on the [SID].bak key, rename the new [SID] key to some other name, change the [SID].bak key back to [SID], and try again to log in as the user.