Sign-in process initialization failure: how to fix it in Windows

What the error means

The message appears on a black screen instead of the sign-in screen: Sign-in process initialization failure. Interactive sign-in process initialization has failed. Please consult the Event Logs for more details. Older Windows versions say logon instead of sign-in. Selecting OK usually brings the same box back, and many people see it in Safe Mode too, which rules out most ordinary startup apps.

Microsoft doesn’t have a dedicated support article for this message. The cause that is documented in vendor knowledge bases is the sign-in screen program itself: Dell, for example, documents the error when its encryption software encrypted executables in System32, including LogonUI.exe, after a Windows feature update. Damaged system files and a failed update are the other likely triggers, so the steps below go from least to most invasive.

If your PC uses BitLocker, have the recovery key ready before you start, because the recovery environment may ask for it. Our BitLocker recovery key guide shows where to find it.

Step 1: Get into the recovery environment

Since Windows never reaches the sign-in screen, use one of the methods Microsoft documents for a PC that won’t start:

• Interrupted boots: turn the PC on, and as soon as Windows starts loading, hold the power button until it switches off. Do this twice. On the third start Windows should open Automatic Repair; select Advanced options.
• Installation media: on another PC, make a Windows USB with the Media Creation Tool, boot the broken PC from it, select Next and then Repair your computer.

Either way you reach the blue Choose an option screen. Our WinRE guide explains the menus in more detail.

Step 2: Run Startup Repair

Go to Troubleshoot > Advanced options > Startup Repair and let it finish. It checks the boot files and some common problems automatically. Results are logged in C:\Windows\System32\LogFiles\Srt\SrtTrail.txt. Users on Microsoft’s forums report mixed results with this error, so if it says it couldn’t repair the PC, move straight on.

Step 3: Uninstall the latest update

If the error started right after Windows installed updates, go to Troubleshoot > Advanced options > Uninstall Updates. Choose Uninstall latest quality update first; if the problem began after a version upgrade, try Uninstall latest feature update instead. Restart and see whether the sign-in screen returns.

Step 4: Use System Restore

If restore points exist, Troubleshoot > Advanced options > System Restore rolls system files and settings back to a date when sign-in worked. Pick a restore point from before the problem started. Your documents aren’t affected, but apps and drivers installed after that date will need reinstalling. If you get an error saying protection is off, see our guide to System Restore protection errors.

Step 5: Repair system files offline

From Troubleshoot > Advanced options > Command Prompt, you can run System File Checker against the installed copy of Windows. Inside the recovery environment the Windows drive often isn’t C:, so check first:

diskpart
list volume
exit

Find the large NTFS volume that holds Windows and note its letter. Then run SFC, replacing C: if needed:

sfc /scannow /offbootdir=C:\ /offwindir=C:\Windows

Microsoft’s boot troubleshooting page uses exactly this syntax. If an update was left half-installed, the same page lists DISM /Image:C:\ /Cleanup-Image /RevertPendingActions to roll back pending actions. Our sfc /scannow guide explains the result messages.

Step 6: Check LogonUI.exe

This step is more advanced. In the same Command Prompt, check whether the sign-in program is where it should be:

dir C:\Windows\System32\LogonUI.exe

If it’s missing or has been renamed, that is very likely the cause. Dell’s fix for its encryption case is to replace LogonUI.exe with a copy from a working PC. The copy must come from the same Windows version, build and architecture (for example Windows 11 24H2, 64-bit); a file from a different build can cause new problems. If disk-encryption or endpoint-security software is installed, also check the vendor’s support site, because its policy may encrypt or block the file again after you replace it.

Last resort: reset and keep your files

If nothing above works, Troubleshoot > Reset this PC with Keep my files reinstalls Windows while keeping your personal files. Apps and settings are removed, so back up anything important first if you can reach the drive from another PC or the recovery Command Prompt.

Related guides

• WinRE: what the Windows Recovery Environment is and how to open it
• How to run sfc /scannow in Windows 11 and 10 (and read the results)
• System Restore “You must enable system protection on this drive”: how to fix it
• Dell BitLocker recovery key: where to find it and why it appears

Official sources

• Windows Recovery Environment (Microsoft Support)
• Advanced troubleshooting for Windows boot problems (Microsoft Learn)
• Dell Encryption displays sign-in process initialization failure (Dell Support)