Windows Defender Cannot Be Activated After Uninstalling Comodo Anti Virus– Help Needed (Windows 10)
Hello Community, I’m experiencing a problem with my Windows 10 laptop and hope to get some guidance. Official support is no longer available for my system, so I’m turning to the community for help. Problem Comodo Anti Virus /Internet Security / Internet Security Essentials had been installed on my laptop for a long time. While Comodo was active, I could not load certain websites properly, and games like League of Legends would not run. For this reason, I recently uninstalled Comodo. After the uninstallation, the previously blocked websites and games work again. Current issue: My Windows Defender Antivirus cannot be activated. In Windows Security, it shows: “Virus & threat protection: Action required” “The threat service has stopped. Start it now” Clicking “Start now” only shows a loading indicator and then an “An unexpected error has occurred” message. I have administrator rights, but Defender still cannot be activated. Steps I’ve Tried 1. Registry checks Path: HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender Checked entries like DisableAntiSpyware and DisableRealtimeMonitoring Modifications often failed → access denied 2. PowerShell commands Set-MpPreference -DisableRealtimeMonitoring $false → errors: “Parameter not found” or “Access denied” Other commands like Set-ItemProperty or Set-Content → errors: “UnauthorizedAccessException” or “InvalidArgument” 3. CMD / SC commands sc config WinDefend start=auto Error: “SC Open Service Error 5 – Access denied” 4. Service check Get-Service WinDefend | Select-Object Status, StartType → Status: Running, StartType: Automatic Despite the service running, Defender cannot be enabled in Windows Security 5. System restore point created (For Comodo Revomal Tool) Drive C: protection enabled Backup created as a precaution Insights / Analysis (Speculations) After uninstalling Comodo, websites and games work again → this suggests that Comodo previously installed network filters or drivers that blocked them. It is possible that remnants of Comodo (drivers, services, registry entries) are preventing Windows Defender from starting. Firewall, App & Browser protection, and Exploit protection are active → partial protection, but Defender is not functional. I am not certain if there are other causes, but based on my experience, it seems strongly related to leftover Comodo components. Has anyone experienced similar issues where Defender remains blocked after uninstalling Comodo? Are there safe methods to fully reactivate Defender without risking system stability? Should I use the official Comodo Removal Tool to remove all remnants? Are there alternative steps to try before using a removal tool? I would greatly appreciate any guidance, tips, or steps I can try to get Windows Defender working again. Thank you in advance!Microsoft Defender fails to update from File Share
Hello! I've tried to configure my Windows system to use Defender Updates through File Share. On my domain controller I've set two GPOs to make it possible. Define file shares for downloading security intelligence updates -> \\fileserver\DefenderUpdates Define the order of sources for downloading security intelligence updates -> FileShares When running the command Get-MpPreference I can see that the GPOs were successful with the following output: SignatureDefinitionUpdateFileSharesSources : \\fileserver\DefenderUpdates SignatureDisableUpdateOnStartupWithoutEngine : False SignatureFallbackOrder : FileShares The file structure on the file share looks like the following: \---DefenderUpdates \---x64 mpam-fe.exe Then I tried to run the command Update-MpSignature and I get the following error message: Update-MpSignature: Virtus and spyware definitions update was complated with errors. At line:1 char:1 + Update-MpSignature + + CategoryInfo : NotSpecified: <MSFT_MpSignature:ROOT\Microsoft\...SFT_MpSignature> [Update-Signature], CimException + FullyQualifiedErrorId : HRESULT 0x8024402c,Update-MpSignature This has worked previously but I don't know what has changed. Does any one have a clue? Best regards, dedicated-worker.
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