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Path starts with \\?\

sleepydog55 1 Reputation point
2021-12-26T22:36:53.883+00:00

I recently setup a software restriction policy in windows 11 pro, default disallow. It broke Windoes defender. Checking the event log it showed access to \?\C:\Windows\System32\SecurityHealthHost.exe was disallowed due to default policy. I tried add an unrestricted rule for C:\Windows\System32\SecurityHealthHost.exe, even though the whole folder was unrestriced but it didn't help. Adding an unrestriced rule for \?\C:\Windows\System32\SecurityHealthHost.exe solved the problem. Has anyone seen path names tha start with \?\ Is this something new with Windows 11? Can anyone explain what \?\ means?

Windows 11
Windows 11
A Microsoft operating system designed for productivity, creativity, and ease of use.
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  1. Andreas Baumgarten 99,046 Reputation points MVP
    2021-12-26T23:32:00.443+00:00

    Hi @sleepydog55 ,

    it looks like a DOS device path format:
    https://learn.microsoft.com/en-us/dotnet/standard/io/file-path-formats#dos-device-paths

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    (If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)

    Regards
    Andreas Baumgarten

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