On 15 Jan 2024 in comp.mail.eudora.ms-windows, DaveH2 wrote:

It isn't possible to have two instances of Eudora running at the
same time on the same machine. You can have two separate
installations of Eudora, as you've done, but you can only run them
one at a time.

I haven't tried it on Win11 as the OP asked, but I frequently have two or
more instances of Eudora running on Win7 and Win10. You set up shortcuts pointing at separate instances of eudora.ini, and you can run any number.

--
Joe Makowiec
http://makowiec.org/
Email: http://makowiec.org/contact/?Joe
Usenet Improvement Project: http://twovoyagers.com/improve-usenet.org/

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 16 Jan 2024 in comp.mail.eudora.ms-windows, DaveH2 wrote:

Eudora and Aurora still cannot be run at the same time though. When
one is running, the other won't open.

Eudora drops an "OWNER.LOK" file in its working directory when it starts running, and won't start another instance IN THAT WORKING DIRECTORY. If
you want to experiment, you may try setting up two separate directories.
Point Aurora at one, Eudora at the other and see if they both run. If
Aurora started from the Eudora code base, I'd suspect that they will.

--
Joe Makowiec
http://makowiec.org/
Email: http://makowiec.org/contact/?Joe
Usenet Improvement Project: http://twovoyagers.com/improve-usenet.org/

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)