I had that error when installing at a “value” hoster. I think their installer script had some issues. When I moved to another host the problem disappeared.
I have today had the dreaded “cannot change the name of an active session” at another testing site where I used Softaculous to install the latest 9.4.2 Concrete.
I tried twice. I delete both instances and tried with a fully manual install from your zip dated 1-july-2025. That had the same issues and I could not login, nor navigate the site more than 2 times.
I have edited a PHP file as below that was throwing the exception. That seems to have stopped the error but most likely has broken something else. I am not a php expert.
The file I edited was AbstractProxy.php and is located in
concrete/vendor/symfony/http-foundation/Session/Storage/Proxy/
In that file I edited out line 113…
which had shown throw new LogicException(‘Cannot change name…’);
I can now log into Concrete 9.4.2 and thus far it runs well.
Perhaps this will enable wiser heads than mine to fix the problem.
Cheers,