Installing CYGWIN 3.6.5 on fresh install of Windows 11 24H2 Build 26100 fails

[J. P. Abelanet]

Brian,

Thanks for the quick reply.  This is a vanilla install, with literally nothing on it other that Windows 11.
In particular, no third-party anti-virus tools have been installed.
I had already tried adding a WD exclusion for C:\cygwin, and turning off Real-time protection and related
switches.

Any other ideas?  This is a Parallels VM, but I’ve used CYGWIN on all my other Parallels VMs for
15 years in a very high usage development environment with no problems.

> On Oct 17, 2025, at 1:25 PM, Brian Inglis via Cygwin <cygwin@cygwin.com> wrote:
> 
> On 2025-10-17 09:23, J. P. Abelanet via Cygwin wrote:
>> When I perform a fresh install of CYGWIN 3.6.5 on a fresh install of Windows 11 24H2 Build 26100,
>> I get the following errors, which prevent even basic functionality from working:
>> Package: 0/Perpetual
>> 	0p_000_autorebase.dash exit code -1073741819
>> 	0p_update-info-dir.dash exit code -1073741819
>> Package: _/base-files
>> 	base-files-mketc.sh exit code -1073741819
>> 	base-files-profile.sh exit code -1073741819
>> Package: _/ca-certificates
>> 	ca-certificates.sh exit code 139
>> Package: _/libsasl2_3
>> 	libsasl2_3.sh exit code -1073741819
>> Package: _/rsnapshot
>> 	rsnapshot.sh exit code 139
>> Package: z/Perpetual
>> 	zp_fontconfig_dtd.dash exit code -1073741819
>> I’ve also tried upgrading an existing, working Windows 11 machine which had CYGWIN 3.5,
>> and I get the exact same problems.
>> I’ve used CYGWIN in production environments for years on various versions of Windows
>> up through Windows 10 with no problems.
>> Is this a known issue, and does anyone have any suggestions?
> 
> Check AV settings, or Windows Defender/Windows Security/Virus and threat protection settings; add exclusions?
> 
> -- 
> Take care. Thanks, Brian Inglis              Calgary, Alberta, Canada
> 
> La perfection est atteinte                   Perfection is achieved
> non pas lorsqu'il n'y a plus rien à ajouter  not when there is no more to add
> mais lorsqu'il n'y a plus rien à retrancher  but when there is no more to cut
>                                -- Antoine de Saint-Exupéry
> 
> -- 
> Problem reports:      https://cygwin.com/problems.html
> FAQ:                  https://cygwin.com/faq/
> Documentation:        https://cygwin.com/docs.html
> Unsubscribe info:     https://cygwin.com/ml/#unsubscribe-simple