Windows 10: For mmc.exe I get "This app has been blocked for your protection"

Thanks for your suggestions. I tried running mmc directly, but I got the same error. And I tried deleting catroot2 and rebooting, but that made no difference either. There was one untoward thing when I was deleting catroot2: when I tried to stop wuauserv I got told that it couldn't be stopped. I assumed that this meant that it was already dead, but could it have still been running and interfered with what I was doing?

 

Since it can't verify the security certificate, it's possible that the Windows Registry has gotten​ corrupt somehow.

You may need to backup all of your personal and important files and do a clean install of Windows

 

It's odd that the system file "MMC.exe" is being blocked like this. You might run a SFC /SCANNOW command to see if the file may be corrupted. Afterwards, try opening it again.

 

Check, if you have any untrusted certificates.
But in order to access them, you need to open mmc. *Rolleyes

You need to enable system admin and then login into that account.

Enable or Disable Elevated Administrator account in Windows 10 Windows 10 User Accounts Tutorials

Then run CMD as admin and run mmc. Expand untrusted certificates only and remove, if any.

Delete Untrusted Root CA Certificates

Antiviruses tend to install theirs certificates and mess up system, it might be worth uninstalling any AV.

 

I get how to delete the untrusted certificates, but how do I work out which ones I shouldn't trust?

 

I've already run sfc /scannow. It said there were some things it couldn't correct and to look in a ludicrously long and non-self-explanatory log file to find out what they were.

 

If you haven't already, run the Dism /Online /Cleanup-Image /RestoreHealth command to repair any component store corruption, restart the PC afterwards, and try the sfc /scannow command again.

 

Sort it by the expiration date and remove expired ones.

You can also remove untrusted list, I have removed "not listed".

 

You're able to open MMC.exe now?

For mmc.exe I get - Windows 10 Forums

 

Think that best would be to run Sigcheck from Sysinternals (there are other similar utilities, but you can trust this one...)

Check also this application called RCC (it's second or third down. It will check certificates and compare them to MS database.

Below is example from its window

Edit: Never mind ... follow TairikuOkami's advice..

 

For future reference, you can run this command at Admin Command prompt to extract only the SR entries to show the errors from SFC /scannow. Substitue your user name for User Name.

It will produce a text file on your Desktop you can open with Notepad.


findstr /c:"[SR]" %windir%\logs\cbs\cbs.log >"c:\users\User Name\desktop\sfcdetails.txt"

 

But what am do I need to look for in the log file? I tried browsing it before, but I didn't know what I was trying to find.

 

You can post the log file in your other thread on this if you like. We'll be happy to look at it, and let you know what it reported as corrupted.

 

OK. Thanks. But how do I post files here? It's not obvious how to do it. And also it would have to be the whole log file because the findstr command didn't produce a file.

 

Here you go: How to Upload and Post Screenshots and Files at Ten Forums Windows 10 Tutorials