Sorry to hear your problems with CentOS Stream 9.   As you have discovered, it is too new for general use.  You are beta testing for  Red Hat Enterprise Linux 9, which is not available yet.  If you want to continue to be a beta tester, report these problems to Red Hat.  For example, the fact that the mesa-libOSMesa package is missing.   Once RHEL 9 comes out, we will work on making a ChimeraX release for it.     HTH,     Greg On 4/19/2022 9:10 AM, Antonio Díaz Quintana via Chimera-users wrote:

Dear all,

I am unable to install Chimerax  and Chimera—yes I still use the old one because its great tools—using the rpm package in Centos Stream 9, because lack of LibOSMesa package in this distribution. I tried using dnf, but a mesa-libGL library (21.3.4...) is already installed

Similarly, it seems my OS distribution does not contain python Tk, nor I can get suitable python with Tk-devel from repository, so I get the following message.

Could I get any help?

Meanwhile I got it on my old Win10, 11 years-old laptop. Both programs work well there.

Best,

Antonio