Windows 10: Lockedout even as administrator

I fired up an infrequently used PC (Lenovo ThinkCentre M53) only to find that I am locked out of several functions such as device manager. A red banner comes up that says:
This app has been blocked for your protection
An administrator has blocked you from running this app. For more information contact the admistrator.

mmc.exe

Publisher: Unknown
File origin: Hard drive on this computer
Program location: "C:\WINDOWS\system32\mmc.exe" C:
\WINDOWS\system32\devmgmt.msc

I can run device manager from Admin version of Windows Powershell

Windows version number is 1903. All my other Win 10 PC's are 2004
Also Windows Update says that I am up to date.

Thank you. John

:)

 

Settings can't be opened using the built-in administrator account


Hello,
Unfortunately I have the same issue as Dabz from upgrading win7 to win10.
I've tried opening settings using all the suggested methods and it will not load using my account with Administrator access nor the built-in Administrator profile. I also tried other methods not listed such as using Run. Control panel is just a stepping stone to add users in Settings.
I'm also having explorer.exe issues, which I believe is preventing Settings from loading.
Using cmd (Admin) I successfully created a new user profile [and granted admin access also using cmd (Admin)], however win10 will not allow this account to log on. win10 does not list this new user within control panel but it does in the start menu. win10 will not allow to log in or switch to the new account via the start menu either.
I can access settings in Safe Mode but this will not allow me to create a new account.
Any help/suggestions will be greatly appreciated.
Cheers

 

Administrator level User

Got the laptop. It's a Lenovo G500 so possibly has Lenovo stuff in the way? Anyway, booted it normally and it opens into a regular account without admin privileges. Rebooted it into Recovery mode (per Option 5) and get Lenovo logo and Preparing Automatic Repair message; then Select Account + "You need to sign in as an administrator to continue but there aren't any administrator accounts on this PC". There is an option "Forgot your password or don't see your account?" but selecting that brings up a screen which should list admin accounts but there aren't any. Pressing the only option on that page Restart leads eventually to a BSOD with Stop code: 0xc00002e3 (which I know is misconfigured o/s or missing or damaged system files).

Can anybody suggest next steps in resolving this?

 

Administrator level User

Use Option Five again, but this time boot from a Windows 10 install usb or recovery drive. You only get asked to select an administrator account if you boot from the system's own Advanced Startup.