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Date: Mon, 2 Mar 2026 21:21:29 +0100
Message-ID: <CANH4o6MQ8yiYfVaA3HajdvTXz-qRkRUhfhzJSiGMskBqx2C5Jw@mail.gmail.com>
Subject: Re: HYPER-V VMs: Cygwin /bin/getent group 'Virtual Machines' cannot
 find the group
To: cygwin AT cygwin DOT com
From: Martin Wege via Cygwin <cygwin AT cygwin DOT com>
Reply-To: Martin Wege <martin DOT l DOT wege AT gmail DOT com>
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On Mon, Mar 2, 2026 at 9:06 PM Bill Stewart via Cygwin
<cygwin AT cygwin DOT com> wrote:
>
> On Mon, Mar 2, 2026 at 12:19 PM Martin Wege wrote:
>
> >
> > Hello,
> >
> > we use HYPER-V virtual machines on Windows 10 and Windows 11. It seems
> > they use a "special" kind of group called 'Virtual Machines', which
> > Cygwin (3.6.5) /bin/getent cannot lookup:
> >
> > getent group 'Virtual Machines'
> > <nothing>
> >
> > Does anyone have ideas or clues how to get getent group to work with
> > this kind of Windows group?
> >
> > We want the Cygwin gid for that group, and use Cygwin commands to work
> > with those files...
>
> Information on this group is in the documentation:
>
> https://learn.microsoft.com/en-us/windows-server/identity/ad-ds/manage/understand-security-identifiers
>
> SID: S-1-5-83-0

$ getent group S-1-5-83-0
Virtual Machines:S-1-5-83-0:339968:
$ getent group 339968
<nothing>
$ getent group 'Virtual Machines'
<nothing>
$ getent group 'Virtual Machines AT NT VIRTUAL MACHINE'
<nothing>
$ getent group 'Virtual Machines+NT VIRTUAL MACHINE'
<nothing>

Why? WHHHHHHYY? ;(

>
> Display name: NT VIRTUAL MACHINE\Virtual Machines
>
> Description: A built-in group. The group is created when the Hyper-V
> role is installed. The Hyper-V Management Service (VMMS) maintains the
> membership of this group. This group requires the 'Create symbolic
> links' right (SeCreateSymbolicLinkPrivilege) and the 'Log on as a
> service' right (SeServiceLogonRight).
>
> Not sure how you use it in Cygwin, though...

Well, we need access to that group for working on VM images, including
creation, modification, backup/restore etc

Thanks,
Martin

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