The login screen loop is a special kind of maddening: you enter the correct password or PIN, Windows appears to sign you in — then dumps you right back at the login screen. Your credentials are fine (wrong passwords give a different error); the problem is that the user session fails to start after authentication succeeds. That narrows the suspects to the user profile, the logon services, credential state, and disk errors on profile folders.

First, determine the scope: does it happen for one account or all accounts? One account = corrupt profile (most common). All accounts = system-wide (services, system files, disk). That single observation directs the whole repair. For the step-by-step variant of this fix, see login screen loop step by step ; for PIN-specific failures, PIN not working step by step .

Why this happens

  • Corrupt user profile: Damaged profile registry data or profile folders — the number one cause for single-account loops.
  • User Profile Service failure: The service that loads profiles failing to start or crashing.
  • Corrupt credential state: Broken Windows Hello, PIN, or Credential Manager data interrupting session setup.
  • Disk errors on profile folders: Bad sectors or filesystem corruption in C:\Users\<name>.
  • Third-party credential providers: Fingerprint software, corporate logon tools, or “tweaks” breaking the logon chain.
  • Corrupt system files: Damaged logon components (winlogon, userinit).
  • Windows update damage: Updates corrupting profile or credential components.

How to fix it

Work through these in order — diagnose first, then act.

Fix 1: Determine the scope — test another account

One test that directs everything.

  1. At the login screen, check whether other user accounts are listed. Try signing into a different account.
  2. Other account works = your profile is corrupt. Skip to Fix 4.
  3. No other account exists or all accounts loop = system-wide. Continue with Fix 2.
  4. If you can’t test another account, boot into Safe Mode (Shift > Restart > Troubleshoot > Advanced options > Startup Settings > 4) — Safe Mode’s minimal profile path often succeeds where normal logon fails.

Fix 2: Check the User Profile Service and Credential Manager

Services that must run for logon to complete.

  1. In Safe Mode (or another working account), press Win + R, type services.msc, press Enter.
  2. Find User Profile Service — it must be Running with Automatic startup. If not, start it and set it to Automatic.
  3. Do the same for Credential Manager and Windows Biometric Service (if you use Hello/fingerprint).
  4. Restart and test logon. A disabled logon service produces exactly this loop.

Fix 3: Repair system files and check the disk

For system-wide loops with no profile distinction.

  1. Open Terminal (Admin) in Safe Mode or a working account.
  2. Run sfc /scannow, then DISM /Online /Cleanup-Image /RestoreHealth.
  3. Run chkdsk C: /f and restart to scan — filesystem damage in the Users folder breaks profile loading.
  4. Restart and test. If SFC repaired logon components, the loop often ends here.

Fix 4: Repair the corrupt user profile via registry

The definitive fix for single-account loops.

  1. Sign into a different administrator account (or enable the built-in Administrator from WinRE Command Prompt: net user administrator /active:yes).
  2. Press Win + R, type regedit, and navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList.
  3. Find your profile’s SID key. If it ends in .bak, that’s the corrupt marker: rename the good key (without .bak) by adding .tmp, remove .bak from yours, then rename .tmp out of the way — or simply delete the .bak key if a duplicate exists and yours is the broken one.
  4. Check the RefCount and State values in your key — set both to 0. Restart and sign in.

Fix 5: Create a new profile and migrate

When registry repair fails or the profile is too damaged.

  1. In a working admin account, go to Settings > Accounts > Other users > Add account and create a new local administrator account.
  2. Sign into it once (this builds a clean profile), then sign out.
  3. Copy your files from C:\Users\<oldname>\Documents, Desktop, Pictures, etc. to the new profile — don’t copy the entire AppData folder, which may carry the corruption.
  4. Reinstall needed applications under the new profile. Keep the old profile until you’re sure everything migrated.

Fix 6: Reset Windows Hello and credential state

For loops tied to PIN, fingerprint, or Hello.

  1. In Safe Mode or a working account, go to Settings > Accounts > Sign-in options.
  2. Under PIN (Windows Hello), choose Remove, then set up the PIN again fresh.
  3. Delete stale credentials: Control Panel > Credential Manager > Windows Credentials > remove entries for the affected account’s services.
  4. Restart and sign in with password first, then re-enroll biometrics. Corrupt Hello containers are a known loop trigger.

Fix 7: Uninstall recent updates and conflicting logon software

The remaining system-wide causes.

  1. Settings > Windows Update > Update history > Uninstall updates — remove the most recent quality update if the loop started after it.
  2. Uninstall third-party credential providers: fingerprint utilities, corporate VPN logon agents, and Start-menu/logon “tweakers” (Settings > Apps > Installed apps).
  3. Check Microsoft’s support site for known logon issues with your build.
  4. Final option: in-place upgrade repair with the Windows 11 ISO (setup > Keep personal files and apps), which rebuilds logon components cleanly.

Closing

The login loop is a session-startup failure, not an authentication failure — and that distinction is the whole diagnosis. One account affected means profile repair or migration; all accounts means services, files, or disk. Work the scope test first and you’ll skip half the list. And once you’re back in, make a second administrator account: the single most useful recovery tool for any future profile problem is another way to sign in. Test the fix by signing out and back in twice — a loop that survives one successful logon can still return on the next.

Frequently asked questions

Why does Windows 11 keep returning me to the login screen?
The sign-in succeeds but the user session fails to start, so Windows drops you back at the login prompt. Common causes: a corrupt user profile, a broken credential manager state, the User Profile Service failing to load, disk errors on the profile folders, or third-party software interfering with logon. The fixes below address each in order.
Will I lose my files fixing a login loop?
No. The repair steps — Safe Mode troubleshooting, profile repair, SFC scans, and credential resets — don’t touch your personal files. Only creating a new profile involves moving files, and that’s a copy operation, not a deletion. Your data remains on the drive throughout.
Can I bypass the login screen to fix the loop?
You can’t skip authentication, but you can reach a working environment: boot into Safe Mode (which uses a minimal profile path) or sign in as a different user account. From there you can repair the broken profile. The Recovery Environment’s Command Prompt is another route that needs no sign-in at all.
What if the login loop affects all user accounts?
If every account loops, the problem is system-wide, not profile-specific: corrupt system files, a broken credential provider, or disk errors. Prioritize SFC/DISM repairs, chkdsk, and checking the User Profile Service and Credential Manager services. Profile-level fixes only help when one account is affected.