Microsoft Account Sign-In Assistant service (wlidsvc) cannot start — System error 5 (Access is denied)

Hello Kandan Lai,

Thank you for contacting Microsoft Q&A Forum.

I understand you’re encountering a critical issue where the Microsoft Account Sign-In Assistant service (wlidsvc) cannot start, returning System error 5: Access is denied on Windows 11 24H2. I appreciate the very detailed troubleshooting steps you’ve already taken.

You are correct in your suspicion. Since DISM and sfc /scannow found no integrity violations, this is almost certainly a security permission (Permissions) issue. Error 5 means the service is being denied access to a resource it needs to run.

So, you can try my suggestions below to correct this:

Solution 1: Verify Service Logon Account (Critical Step)

This is the most common cause for Error 5 on this specific service. It must not run as "Local System".

1. Press Windows + R, type services.msc, and press Enter.
2. Locate Microsoft Account Sign-In Assistant.
3. Right-click > Properties > Log On tab.
4. Ensure it is set to "This account".
5. The account name must be NT SERVICE\wlidsvc. If it is set to "Local System" or anything else, this is the error.
6. To fix it: Select "This account", type NT SERVICE\wlidsvc in the box, and delete everything from both the "Password" and "Confirm password" fields.
7. Click Apply, then OK.
8. Restart your PC and try to start the service.

Solution 2: Reset Default Service Security Descriptor

Since you already tried sc sdset, let's run the definitive command to restore the default security permissions (DACL) for this service.

1. Open Command Prompt (Run as Administrator).
2. Copy and paste the entire command below and press Enter:
   sc sdset wlidsvc D:(A;;CCLCSWRPWPDTLOCRRC;;;SY)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;BA)(A;;CCLCSWLOCRRC;;;IU)(A;;CCLCSWLOCRRC;;;SU)(A;;CR;;;AU)(A;;CCLCSWRPWPDTLOCRRC;;;NS)
3. You should see [SC] SetServiceObjectSecurity SUCCESS.
4. Restart your PC.

If steps 1 and 2 fail, the service permissions or related identity components are too corrupted to fix manually. The safest and most effective solution is an in-place upgrade.

This will reinstall Windows 11 while keeping all your personal files, apps, and settings. It rebuilds all system services and permissions to their correct state.

1. Go to the official Microsoft site: https://www.microsoft.com/software-download/windows11
2. Download the Windows 11 Installation Media tool (or the ISO for version 24H2).
3. Run the tool and select "Upgrade this PC now" (or run setup.exe from the mounted ISO).
4. Follow the prompts. Most importantly, ensure you are on the "Ready to install" screen, and it confirms you will "Keep personal files and apps".
5. Let the process complete. This will likely resolve the wlidsvc failure.

The issue you are facing involves complex system security descriptors. If the in-place upgrade does not resolve the problem, this indicates a deep-seated profile or registry issue.

At that point, I strongly recommend contacting Microsoft Support directly via Customer service phone numbers - Microsoft Support. This issue may require real-time remote assistance from a support engineer to safely restore identity services.

Best Regards.

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