Interactive Troubleshooter

Published: Sep 12, 2026

User Profile Service Failed Logon: Create New Profile Without Losing Data

Time: 15 mins Level: Beginner

By StepDiag Engineering Team

Reviewed by Ibraheem Taofeeq Opeyemi

Comprehensive root-cause diagnostic tree for resolving the 'User Profile Service failed the logon' error and temporary profile loops in Windows. Covers NTUSER.DAT hive corruption repair, SID registry key rebuilding under ProfileList, corrupt profile data migration, and domain profile sync fixes.

Full Diagnostic Tree & Step-by-Step Overview

What specific error state or screen behavior occurs when attempting to log into Windows?

Logon stops immediately with explicit message 'The User Profile Service failed the logon. User profile cannot be loaded.'
Logon succeeds, but Windows boots into a 'You've been signed in with a temporary profile' notification.
Logon hangs indefinitely on a black screen or 'Preparing Windows' spinner.
Domain or Active Directory user logon fails specifically with 'The security database on the server does not have a computer account for this trust relationship.'

What is the status of the local registry SID entry under ProfileList for the affected user account?

The user Security Identifier (SID) key under ProfileList has a '.bak' extension appended to it.
The registry SID key is completely missing or points to a non-existent directory path.
The NTUSER.DAT hive file inside C:\Users\[Username] is locked, unreadable, or corrupted.

Clearing Registry SID Duplicate .bak Extension to Restore Original Profile

Solution:

Root Cause: Security Identifier (SID) Registry Key Mismatch

When Windows loads a user profile during the authentication phase, the User Profile Service (profsvc) queries HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList. If the OS detects file corruption in NTUSER.DAT during a prior shutdown or update, it renames the original SID key with a .bak extension and creates a temporary stub key to prevent complete boot failure. Subsequent logon attempts fail because profsvc encounters an invalid state pointer between the live SID key and the .bak backup key.

# Diagnostic Verification:

Inspect Event Viewer under Windows Logs > System for Event ID 1500, 1502, or 1511 from source User Profiles Service.

Verify registry keys via PowerShell in Safe Mode or from an alternate admin account:

powershell
  Get-ChildItem "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList" | Select-Object PSChildName

Check if a folder ending in .bak exists alongside a matching folder without .bak.

# Step-by-Step Fix:

1. Boot into Safe Mode or Log in to a Secondary Administrator Account:

Hold Shift while clicking Restart at the Windows sign-in screen. Navigate to Troubleshoot > Advanced Options > Startup Settings > Restart, then press 4 or F4 for Safe Mode.

2. Open Registry Editor (regedit):

Navigate to: HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList

3. Resolve the Duplicate SID Keys:

Locate the target user SID starting with S-1-5-21-...

If there are two identical SID keys—one without .bak and one with .bak:

Right-click the key without .bak, click Rename, and append .old to the end.

Right-click the key with .bak, click Rename, and remove .bak entirely.

4. Reset State and RefCount Flags:

Select the newly renamed key (now without .bak).

In the right pane, double-click RefCount and set Value data to 0.

Double-click State and set Value data to 0.

Verify ProfileImagePath points to the correct user folder (e.g., C:\Users\John).

5. Close Registry Editor and restart Windows normally.

# Prevention & Long-Term Monitoring:

Ensure applications do not forcibly terminate during logoff, which prevents NTUSER.DAT registry hives from cleanly unmounting.

Rebuilding Missing ProfileList Registry Pointer Settings

Solution:

Root Cause: Missing ProfileList Registry Key Entry

If the SID registry subkey corresponding to a specific user account is accidentally deleted or corrupted beyond recognition, profsvc cannot resolve the user's home folder path (ProfileImagePath). Although the user's data directory still exists on disk at C:\Users\[Username], Windows rejects the logon sequence because the essential registry metadata mapping is missing.

# Diagnostic Verification:

Obtain the exact user SID via PowerShell:

powershell
  Get-WmiObject -Class Win32_UserAccount | Where-Object {$_.Name -eq "TargetUsername"} | Select-Object Name, SID

Open regedit and navigate to HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList to verify that the key matching the returned SID does not exist.

# Step-by-Step Fix:

1. Re-create the Missing Registry SID Key:

In regedit, navigate to HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList.

Right-click ProfileList > New > Key.

Name the key with the exact SID retrieved from PowerShell (e.g., S-1-5-21-xxxx-xxxx-xxxx-1001).

2. Populate Required Value Entries:

Inside the new SID key, create the following values:

Expandable String Value (REG_EXPAND_SZ) named ProfileImagePath with data set to C:\Users\[Username] (replace [Username] with actual folder name).

DWORD (32-bit) Value (REG_DWORD) named State set to 0.

DWORD (32-bit) Value (REG_DWORD) named RefCount set to 0.

DWORD (32-bit) Value (REG_DWORD) named Sid set to binary format or standard default.

DWORD (32-bit) Value (REG_DWORD) named Flags set to 0.

3. Verify NTFS Security Permissions on User Folder:

Open Command Prompt as Administrator and restore ownership of the user directory:

cmd
     icacls "C:\Users\[Username]" /setowner "Domain\TargetUsername" /T /C
     icacls "C:\Users\[Username]" /grant "Domain\TargetUsername":(OI)(CI)F /T /C

4. Restart the system and attempt user logon.

# Prevention & Long-Term Monitoring:

Export a backup of HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList before making system image changes or user management operations.

Provisioning a New Local Profile and Safely Migrating Corrupted Profile Data

Solution:

Root Cause: Irrecoverable NTUSER.DAT Registry Hive File Corruption

When the primary user registry hive file C:\Users\[Username]\NTUSER.DAT suffers filesystem cluster damage or corruption during write operations, Windows cannot mount HKEY_CURRENT_USER. Because the hive structure is corrupted at the file system level, repairing registry entries will not restore functionality. Creating a fresh profile and migrating personal data files to the new profile structure is required.

# Diagnostic Verification:

Attempt to manually mount the corrupted hive via PowerShell:

powershell
  reg load HKLM\TestHive "C:\Users\TargetUser\NTUSER.DAT"

If PowerShell returns ERROR_NOT_REGISTRY_FILE or The process cannot access the file because it is being used by another process, the hive file is structurally broken.

# Step-by-Step Fix:

1. Create a New Local Administrator Account:

Boot into Safe Mode or log in with an alternate working Admin account.

Open Admin PowerShell and run:

powershell
     New-LocalUser -Name "NewAdmin" -Password (ConvertTo-SecureString "TempPass123!" -AsPlainText -Force) -FullName "New Account"
     Add-LocalGroupMember -Group "Administrators" -Member "NewAdmin"

2. Log Into the New Account to Initialize Directory Structure:

Log out and log into NewAdmin. This builds the clean profile tree under C:\Users\NewAdmin.

Log out of NewAdmin and log back into your primary fallback administrator account.

3. Migrate User Data Files manually:

Open File Explorer and navigate to C:\Users\[CorruptedUser].

Ensure hidden files and system items are visible (View > Show > Hidden items).

Select and copy all personal data folders:

Documents, Downloads, Pictures, Videos, Music, Desktop

AppData\Roaming (Select application configuration data as needed, e.g., browser profiles)

CRITICAL: Do NOT copy NTUSER.DAT, NTUSER.DAT.LOG*, or ntuser.ini from the old profile, as doing so will copy the corruption into the new account.

Paste copied data into C:\Users\NewAdmin (or a newly assigned clean username folder).

4. Re-assign Folder Ownership:

Open Admin Command Prompt and execute:

cmd
     takeown /f "C:\Users\NewAdmin" /r /d y
     icacls "C:\Users\NewAdmin" /grant NewAdmin:(OI)(CI)F /T

5. Consult official details in the Microsoft Fix Corrupted User Profile Guide for additional domain-joined profile migration steps.

# Prevention & Long-Term Monitoring:

Maintain automated backups of critical user directories to cloud or network storage using OneDrive or Windows Backup.

What occurs when you sign out of the temporary profile and attempt to log in again?

The temporary profile loads repeatedly on every sign-in attempt.
The sign-in process fails completely after logoff with an error message.

Fixing Persistent Temporary Profile Loops and Cleaning Temp Hives

Solution:

Root Cause: Profile State Flag Locks and Temp Directory Staging

A persistent temporary profile loop occurs when Windows creates a dynamic directory C:\Users\TEMP or C:\Users\TEMP.[Domain] because it cannot gain exclusive file locks on the primary user folder. This is frequently caused by background security software, backup agents, or antivirus real-time scanners holding open handles to NTUSER.DAT during system shutdown.

# Diagnostic Verification:

Check the logged-in user profile path in Command Prompt:

cmd
  whoami /user
  echo %USERPROFILE%

If %USERPROFILE% returns C:\Users\TEMP, the session is running on an ephemeral hive.

# Step-by-Step Fix:

1. Identify and Terminate Process Handles Holding NTUSER.DAT:

Download and run Handle from Microsoft Sysinternals, or execute via PowerShell to check for open locks on the target path:

powershell
     Get-Process | Where-Object {$_.Path -match "antivirus|backup"}

2. Clean Temporary Profile Entries in Registry:

Log into a separate Administrator account.

Open regedit and navigate to: HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList

Delete any temporary SID keys ending in .bak or pointing to C:\Users\TEMP in their ProfileImagePath.

3. Remove Temporary Folders from Disk:

Delete the folder C:\Users\TEMP completely.

4. Modify Group Policy to Wait for Network and Process Termination:

Press Win + R, type gpedit.msc, and press Enter.

Navigate to Computer Configuration > Administrative Templates > System > User Profiles.

Enable Set user profile status to local when domain profile fails.

Enable Do not forcefully unload the user registry at user logoff.

5. Reboot the system and log in with the primary user account.

# Prevention & Long-Term Monitoring:

Configure antivirus exclusions for C:\Users\*\NTUSER.DAT* to prevent real-time scanning file locks during logoff routines.

Where in the boot or initialization sequence does the logon process freeze?

Freezes at 'Welcome' or 'Preparing Windows' screen for over 10 minutes.
Logon succeeds to a black screen with only a mouse cursor visible.

Resolving AppX Deployment Service (AppXSvc) Initialization Stalls

Solution:

Root Cause: AppX Package Registration and Firewall Service Deadlocks

During the 'Preparing Windows' phase of user logon, the User Profile Service coordinates with the AppX Deployment Service (AppXSvc) and Windows Push Notifications System Service (wpnservice) to register UWP/AppX packages for the user session. If AppXSvc hits a deadlock due to corrupted package repositories in C:\ProgramData\Microsoft\Windows\AppRepository, or if the Windows Defender Firewall service is disabled, package staging halts indefinitely.

# Diagnostic Verification:

Inspect Event Viewer logs via remote PowerShell or Safe Mode under Applications and Services Logs > Microsoft > Windows > AppXDeployment-Server > Operational.

Look for Event ID 5900 or 6000 indicating package registration timeouts.

# Step-by-Step Fix:

1. Ensure Windows Defender Firewall Service is Running:

Universal Windows Platform (UWP) profile initialization requires active firewall sockets.

Open Admin PowerShell and run:

powershell
     Set-Service -Name mpssvc -StartupType Automatic
     Start-Service -Name mpssvc

2. Reset AppX Package State for Default Provisioned Apps:

Run the following PowerShell command in Safe Mode to repair system package manifests:

powershell
     Get-AppXPackage -AllUsers | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml"}

3. Clear Windows Notification Database Cache:

Navigate to C:\Users\[Username]\AppData\Local\Microsoft\Windows.

Delete or rename wpndatabase.db.

4. Reboot the machine to test profile loading speed.

# Prevention & Long-Term Monitoring:

Avoid disabling core Windows services (such as mpssvc or AppXSvc) through aggressive optimization scripts.

Fixing Shell Infrastructure Host and Desktop Shell Loading Failures

Solution:

Root Cause: Explorer.exe Process Initialization and Shell Hardware Detection Failure

Logging in to a black screen with only a cursor indicates that authentication and profile loading succeeded, but the user shell (explorer.exe) failed to launch or crashed immediately due to corrupted shell extensions, graphics driver initialization delays, or broken Winlogon registry keys.

# Diagnostic Verification:

Press Ctrl + Shift + Esc to open Task Manager.

Click File > Run new task.

Type cmd.exe and press Enter. Run:

cmd
  tasklist | findstr /i "explorer.exe"

If explorer.exe is not running, the desktop shell failed to start.

# Step-by-Step Fix:

1. Verify Winlogon Shell Registry Value:

In Task Manager, run regedit.exe via Run new task.

Navigate to: HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon

Verify that the string value Shell is set strictly to explorer.exe.

Verify that Userinit is set to C:\Windows\system32\userinit.exe,.

2. Manually Launch Desktop Shell:

In Task Manager, click Run new task, type explorer.exe, and press Enter.

3. Disable Problematic Third-Party Shell Extensions:

Open Admin PowerShell and run System File Checker to repair system dependencies:

powershell
     sfc /scannow
     dism /online /cleanup-image /restorehealth

4. Restart display driver in session using keyboard shortcut Win + Ctrl + Shift + B.

# Prevention & Long-Term Monitoring:

Keep graphics adapter drivers updated and avoid installing unverified file explorer customization tools.

What is the domain controller connectivity status for the affected machine?

Machine is disconnected from corporate network / domain controller.
Machine is connected to domain, but computer secure channel trust relationship is broken.

Configuring Cached Interactive Credentials and Kerberos Offline Authentication

Solution:

Root Cause: Active Directory Domain Controller Unavailability and Cached Logons Exhaustion

When a domain-joined laptop attempts to log in off-network without access to a Domain Controller (DC), Windows relies on Local Security Authority (LSA) cached credentials. If cached logons are disabled via Group Policy (cachedlogonscount = 0) or if the Kerberos ticket cache is invalid, profsvc cannot validate domain credentials or download roaming profiles.

# Diagnostic Verification:

Test Active Directory Domain Controller connectivity via PowerShell:

powershell
  Test-ComputerSecureChannel

If it returns False or fails to connect, offline domain authentication must be configured.

# Step-by-Step Fix:

1. Connect Machine to Corporate Network via Ethernet or Pre-Logon VPN:

Ensure physical connection to the internal network or initiate a pre-logon VPN connection at the Windows sign-in screen.

2. Verify/Enable Cached Logon Count in Local Group Policy:

Open gpedit.msc and navigate to Computer Configuration > Windows Settings > Security Settings > Local Policies > Security Options.

Locate Interactive logon: Number of previous logons to cache (in case domain controller is not available).

Set value to 10 (default) or higher.

3. Flush Local Kerberos Tickets:

Open Command Prompt as Administrator and run:

cmd
     klist purge

4. Log in using domain credentials while connected to the network to refresh local security tokens.

# Prevention & Long-Term Monitoring:

Deploy Always On VPN (AOVPN) to ensure domain controller connectivity is established automatically prior to user sign-in.

Resetting Active Directory Computer Account Secure Channel Trust Relationship

Solution:

Root Cause: Broken Computer Account Secure Channel Password

Domain-joined workstations automatically negotiate their computer account password with Active Directory every 30 days. If a machine is restored from an old backup snapshot or remains offline for extended periods, the local password stored in the LSA secret desynchronizes from the password attribute (unicodePwd) on the Domain Controller. Consequently, domain user profiles cannot be authenticated or created.

# Diagnostic Verification:

Run the secure channel test in Admin PowerShell:

powershell
  Test-ComputerSecureChannel -Verbose

An error output of The secure channel check failed. Trust relationship broken confirms the desynchronization.

# Step-by-Step Fix:

1. Log in with a Local Administrator Account:

2. Repair Secure Channel via PowerShell with Explicit Domain Admin Credentials:

Execute in Admin PowerShell:

powershell
     Reset-ComputerMachinePassword -Credential (Get-Credential) -Server "DC01.domain.com"

3. Alternative Method: Re-join the Workstation to the Domain:

If PowerShell reset fails, disjoin the computer to a Workgroup and rejoin:

powershell
     Remove-Computer -UnjoinDomaincredential (Get-Credential) -Workgroup "WORKGROUP" -Force -Restart

After rebooting, rejoin the domain:

powershell
     Add-Computer -DomainName "domain.com" -Credential (Get-Credential) -Restart

4. After rebooting, test domain user profile logon.

# Prevention & Long-Term Monitoring:

Avoid reverting domain-joined virtual machines to old snapshots without disabling automatic computer password changes beforehand.

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