HP Laptop Windows 10 blocks a Microsoft Diagcab WinSecurity.exe

Hi BARRY G.VARGUS Sr.

I really appreciate the detailed explanation—this sounds incredibly frustrating, especially since you're the Owner and Administrator, yet Windows Security keeps blocking access as if someone else is in control. Let's break this down and tackle both issues:

Issue 1: Windows Security Troubleshooter Not Recognizing Windows Defender

Since the Windows Security Troubleshooter claims it can't detect your firewall, but you know Windows Defender is active, try these steps:

> Verify Windows Defender Firewall is Actually Running

Open Command Prompt (Admin) and run:

powershell

Get-Service | Where-Object {$_.DisplayName -like "*Windows Defender Firewall*"}

If the service isn’t running, restart it with:

powershell

net start mpssvc

> Reset Windows Defender Firewall

Open Command Prompt (Admin) and run:

powershell

netsh advfirewall reset

Restart your PC and check if the Troubleshooter recognizes it.

> Check Group Policy Settings (If Applicable)

Open Run (Win + R) and type:

gpedit.msc

Navigate to:

Computer Configuration > Administrative Templates > Network > Network Connections > Windows Defender Firewall

Ensure "Turn off Windows Defender Firewall" is NOT enabled.

Issue 2: Controlled Folder Access Blocking Apps (Even After Disabling It)

Since Controlled Folder Access keeps blocking apps even after you turn it off, try these fixes:

> Manually Allow Blocked Apps

Open Windows Security > Virus & Threat Protection > Ransomware Protection.

Click "Allow an app through Controlled Folder Access".

Add CCleanerUpdate64.exe, DST.exe, and HP DIAG manually.

> Disable Controlled Folder Access via PowerShell

If toggling it off in settings doesn’t work, force-disable it:

Open PowerShell (Admin).

Run:

powershell

Set-MpPreference -EnableControlledFolderAccess Disabled

Restart your PC and check if the issue persists.

> Reset Windows Security Policies

If Windows Security is still blocking apps, reset its policies:

Open Command Prompt (Admin).

Run:

powershell

secedit /configure /cfg %windir%\inf\defltbase.inf /db defltbase.sdb /verbose

Restart your PC.

Perform Repair in-place upgrade: This will reinstall your Operating System and will keep your files and apps. This will take some time depending on the computer performance and internet speed. You can follow the steps from this link: How to do a Windows 10 Repair Upgrade - Microsoft Community

Let me know if any of these solutions work for you!

Best Regards,

Lonex P.

Microsoft Moderator

I shut off the Smart screen and firewall completely nothing worked. Also, the WinSecurity Diiagcab can not be run as Administrator.

Hello Lonex,
I think I may have not explained it correctly. The WinSecurity.diagcab a/k/a Windows Security Troubleshooter is a separate thing. I downloaded it and ran it for the first time a few nights ago because of the Blocked Access in Windows Security to see if it would fix it. Windows Security Troubleshooter, the first few times until tonight, mentioned something like W Sec Troubleshooter can't identify your Firewall or find your Firewall, also mentioning Windows Defender is not your Default Firewall. Until tonight "Troubleshooting couldn't identify the problem. Problem being is I am the Owner and Administrator and it is definitely set as the Default Firewall and is turned on in all the proper places. That's a separate issue; however, it stumps me how a Windows app can't detect a Windows Firewall.
I ran that because of all the Protected Memory Access Blocked. Virus and Protection > Protection History > 14 different Protected Memory Access Blocked notifications inside most belonging to MS, HP, Windows, and CCleaner, which were never blocked before starting 8 AM 04/21/2025 to 04/24/2025 at 2:29 PM. I used to be able to see all 14 paths and wish I could now, but it doesn't display the paths or names like CCleanerUpdate64.exe or partial DST.exe an HP DIAG/diag, whatever. I'm no computer wiz and forget most of the names and paths. I do know that there was at least one each of the Microsoft, Windows, and HP files or whatever that was Blocked. Now, when I click on any one of the 14 Blocked items, the box pops up like it's supposed to, asking: Do you want to allow this app to make changes to your device? YES - NO and I click on YES instead of it performing whatever function it performs and allows access by clicking on YES instead it shows the same item in the same place inside Windows Security > Virus and Threat Protection > Protection History Reading: how it was blocked again stating "Your Administrator has blocked this action" where I now see beneath this first one App or process blocked: DST.exe Protected Folder: \Device\Harddisk0\DRO - whatever that is. Blocked by: Controlled Folder Access. You should allow apps to access your protected memory, but you should only allow apps that you trust. Underneath in blue: Controlled Folder Access settings. I can and have clicked on that, toggled the controlled folder access to OFF, and tried again to tap YES only to have it displayed as typed above Exactly the same. Your Administrator...
So, although I'm the Owner and Administrator, it's telling me the Administrator has blocked access to this and the other 13 actions. Crazy huh. I hope that gives you a better understanding of what I'm facing and hopefully to be able to give advice if possible.
Thank you very much!
Respectfully,
Barry

Hi BARRY G.VARGUS Sr.

Thank you for posting in Microsoft Community.

I understand the issue you are facing with downloading the WinSecurity Diagcab on your HP ENVY laptop running Windows 10. To address your concerns:

Possible Fixes

Temporarily Disable Windows Defender SmartScreen – Go to Settings > Privacy & Security > Windows Security > App & Browser Control, then turn off SmartScreen for Microsoft Edge and SmartScreen for Microsoft Store apps.

Manually Allow the File in Windows Defender – Open Windows Security, go to Virus & Threat Protection > Protection History, find the blocked file, and select Allow.

Run the File as Administrator – Right-click the WinSecurity.exe, select Run as Administrator, and see if it bypasses the restriction.

Check Windows Firewall Rules – Open Windows Defender Firewall, go to Advanced Settings > Inbound Rules, and ensure that Diagcab files are not being blocked.

Use PowerShell to Unblock the File – Open PowerShell (Admin) and run:

Unblock-File -Path "C:\Users\YourUsername\Downloads\WinSecurity.exe"

This removes any security restrictions on the file.

Try Downloading in Safe Mode – Boot into Safe Mode with Networking (Shift + Restart > Troubleshoot > Advanced Options > Startup Settings > Restart > Select Safe Mode with Networking) and attempt the download again.

Perform Repair in-place upgrade: This will reinstall your Operating System and will keep your files and apps. This will take some time depending on the computer performance and internet speed. You can follow the steps from this link: How to do a Windows 10 Repair Upgrade - Microsoft Community

Let me know if any of these solutions work for you!

Best Regards,

Lonex P.

Microsoft Moderator