i accidentally deleted windows security how do i reinstall it?

Question

so my computer is messed up so SOMEHOW the windows security whole app got deleted litearlly i still see it as a app but when i open it nothing opens and i tried other things like running it from the run app and stuff like that it also sometimes says you will need a new app to open this windws defender link. if anbody could pls help me with this problem with my computer like i cant open the microsoft store but thats for another forum

Answer 1

Hello there，

You can try actions as follows：
Plan A

1. Enter “powershell” in windows search bar，right click it and “run as administer”；
2. Enter these commands
   DISM.exe /Online /Cleanup-image /Scanhealth
   DISM.exe /Online /Cleanup-image /Checkhealth
   DISM.exe /Online /Cleanup-image /Restorehealth
   

Plan B

1. Open Settings> Windows Update> Check for updates;
   
2. Run Windows update to update your system,
   See if there is a patch for Windows Defender to update,
   Updating your system may solve this problem.

Plan C

1. If you have installed a third-party security software, your windows defender will enter disabled mode by default.
2. In that case, uninstall the third-party security software.

Referring to your Microsoft Store issue

1. If the Store app doesn't open, hangs, or not working correctly, then re-registering the Store will usually fix this issue.
2. Terminate the Microsoft Store app to make sure it's closed and not running.
3. Enter “powershell” in windows search bar，right click it and “run as administer”；
4. Enter this command

Get-AppXPackage WindowsStore -AllUsers | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register “$($_.InstallLocation)\AppXManifest.xml”}

5. When finished, close the elevated PowerShell,
Restart the computer to apply.
Try opening the Microsoft Store app again.

OR the problem may caused by current user’s profile broken, in that case you may try to create another account to see if it is ok.

Best Regards,
Samson Peng

Answer 2

Try download and run a full system scan with:
https://learn.microsoft.com/en-us/windows/security/threat-protection/intelligence/safety-scanner-download
Take a look at:
https://support.microsoft.com/en-us/sbs/windows/fix-windows-update-errors-18b693b5-7818-5825-8a7e-2a4a37d6d787
And
https://support.microsoft.com/en-us/windows/troubleshoot-problems-updating-windows-10-188c2b0f-10a7-d72f-65b8-32d177eb136c

Answer 3

@microsoft user 231476

Kindly Perform Below steps and let us know if you still getting the error

To stop and then restart these services by using a batch file, follow these steps:

Click Start, type Notepad in the Search box and then click Notepad in the programs list.

Select the following text, right click the selected text, and then click Copy. Right-click anywhere in the Notepad window, and then click Paste.

sc config MpsSvc start= auto
sc config KeyIso start= auto
sc config BFE start= auto
sc config FwcAgent start= auto
net stop MpsSvc
net start MpsSvc
net stop KeyIso
net start KeyIso
net start Wlansvc
net start dot3svc
net start EapHostnet
net stop BFE
net start BFE
net start PolicyAgent
net start MpsSvc
net start IKEEXT
net start DcaSvcnet
net stop FwcAgent
net start FwcAgent
In Notepad, Click File, click Save As, and then type Repair.bat in the File name box

Click the Save as type box, and then click All Files (.).

In the left pane, click Desktop, and then click Save.
In the left pane, click Desktop, and then click Save.

On the File menu, click Exit.

On your desktop, right-click the Repair.bat file that you saved in step 5, and then click Run as administrator.

Important If you are prompted for confirmation to stop a service, press Y on the keyboard, and then press Enter