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<p>I assume the system is up-to-date with Cumulative Updates?</p><p><br></p><p>Try removing Defender and Defender GUI via Add/Remove Features.</p><p>If thats successful re-add Defender and GUI via Features.</p>
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<p>you can run sfc or dism</p><p>sfc / scannow&nbsp;</p><p>&nbsp;DISM.exe /Online /Cleanup-Image /Restorehealth (takes 15 - 20 minutes).</p>
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System administrator

SooHow Cheng

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Hi Michael,<br />
<br />
Can't find Windows Defender in Add/Remove.
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Hi nobus,<br />
<br />
Have done it, but nothing.
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<div class="content wysiwyg-content fr-view">
<p>This is about my MS Windows Server 2016 HyperV Vm. Initially, Trendmicro worry-free anti-virus was installed. This "forced" MS Windows Defender off. Recently, my management wanted to standardize to us MS Windows Defender across the board, so Trend Micro antivirus was uninstalled. All the Trendmicro services removed, installation folders removed as well as all Trend Micro-related registry (HKLM\System\CurrentControlSet\Services). Server is rebooted.</p><p>In the Task Manager, no trace of Trend Micro process is running. However, found that MS Windows Defender is still not running. Attempt to start Windows Defender Service ends up with error messages - Error 577: Windows cannot verify the digital signature for this file. A recent hardware or software change might have installed a file that is signed incorrectly or damaged, or that might be malicious software from an unknown source.&nbsp;</p><p>How to get defender work again?</p><p><br></p><p>Thanks,</p>
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This is about my MS Windows Server 2016 HyperV Vm. Initially, Trendmicro worry-free anti-virus was installed. This "forced" MS Windows Defender off. Recently, my management wanted to standardize to us MS Windows Defender across the board, so Trend Micro antivirus was uninstalled. All the Trendmicro services removed, installation folders removed as well as all Trend Micro-related registry (HKLM\System\CurrentControlSet\Services). Server is rebooted.
In the Task Manager, no trace of Trend Micro process is running. However, found that MS Windows Defender is still not running. Attempt to start Windows Defender Service ends up with error messages - Error 577: Windows cannot verify the digital signature for this file. A recent hardware or software change might have installed a file that is signed incorrectly or damaged, or that might be malicious software from an unknown source. 
How to get defender work again?
Thanks,


I assume the system is up-to-date with Cumulative Updates?
Try removing Defender and Defender GUI via Add/Remove Features.
If thats successful re-add Defender and GUI via Features.


you can run sfc or dism
sfc / scannow 
 DISM.exe /Online /Cleanup-Image /Restorehealth (takes 15 - 20 minutes).

Hi Michael,

Can&#39;t find Windows Defender in Add/Remove.

Why MS Windows Defender not working?


This is about my MS Windows Server 2016 HyperV Vm. Initially, Trendmicro worry-free anti-virus was installed. This &quot;forced&quot; MS Windows Defender off. Recently, my management wanted to standardize to us MS Windows Defender across the board, so Trend Micro antivirus was uninstalled. All the Trendmicro services removed, installation folders removed as well as all Trend Micro-related registry (HKLM\System\CurrentControlSet\Services). Server is rebooted.
In the Task Manager, no trace of Trend Micro process is running. However, found that MS Windows Defender is still not running. Attempt to start Windows Defender Service ends up with error messages - Error 577: Windows cannot verify the digital signature for this file. A recent hardware or software change might have installed a file that is signed incorrectly or damaged, or that might be malicious software from an unknown source. 
How to get defender work again?
Thanks,

This topic area includes legacy versions of Windows prior to Windows 2000: Windows 3/3.1, Windows 95 and Windows 98, plus any other Windows-related versions including Windows Mobile.

Windows OS

Windows Server 2016 is the successor to Windows Server 2012 R2. Built upon the same core code as Windows 10, Windows Server 2016 brings enhancements in security, servicing, and connectivity. A particular focus on this release was hybrid-cloud scenarios, and has close ties to Azure and other Microsoft cloud initiatives. This does not detract from the many improvements that are available for on-premises-only deployments

Windows Server 2016 comes in Datacenter, Standard, and Essentials editions, and for servicing, has adopted windows 10's cumulative model. The new nano-server install is designed to be remotely managed and is designed to be kept current through continuous feature updates. The full GUI install operates similarly to windows 10's "Long Term Servicing Branch" (LTSB) model with cumulative security updates.

Windows Server 2016 has also shifted from a per-processor-and-CAL licensing model to a per-core-and CAL licensing model. This brings Windows Server's licensing more in line with Microsoft's other products and makes hybrid-cloud license planning easier as well.

Windows Server 2016

Windows 10 is a personal computer operating system featuring the "universal application architecture" (UAP); apps can be designed to run across multiple devices with nearly identical code, including PCs, tablets, smartphones, embedded systems, Xbox One, Surface Hub and HoloLens. Windows 10 also includes a virtual desktop system, a window and desktop management feature called Task View, the Microsoft Edge web browser, support for fingerprint and face recognition login, voice-based search (Cortana), new security features for enterprise environments, and DirectX 12 and WDDM 2.0 to improve the operating system's graphics capabilities for games.

Windows 10

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