Recently, I made an update to my laptop and it stopped connecting to a server via RDP, showing the below message.

[Window Title]
Remote Desktop Connection

[Content]
An authentication error has occurred.
The function requested is not supported

Remote computer: XXX.XXX.XXX.XXX
This could be due to CredSSP encryption oracle remediation.
For more information, see https://go.microsoft.com/fwlink/?linkid=866660

[OK]

After some internet searches, I came across this article - https://www.virtualizationhowto.com/2018/05/windows-10-rdp-credssp-encryption-oracle-remediation-error-fix/. This explains that the issue is because of latest updates not allowing access to unpatched servers, and explaining how to change your settings to allow connecting even to unpatched servers. In an ideal world, the server would be patched and this would not be an issue. However, that might not happen for a while and I need to find a workaround.

The first issue seems that Windows 10 Home does not have the Group Policy Editor installed. I managed to find an article showing how to get the gpedit.msc back.

However, then I couldn't find the entry Computer Configuration >> Administrative Templates >> System >> Credentials Delegation >> Encryption Oracle Remediation. explained in the article about the update. Again, I am assuming this is because I am using Windows Home 10.

Any ideas how to fix this issue on Windows 10 Home?

  • regedit → HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\
  • Create a key named CredSSP
  • In CredSSP, create a key named Parameters
  • In Parameters, create a DWORD (32) Value named AllowEncryptionOracle
  • Double click AllowEncryptionOracle and change its value to 00000002

You don't have to reboot.

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