Ubuntu 20.10 cannot run previously working Slicer version

@Greydon_Gilmore have a look at this post https://discourse.slicer.org/t/cant-start-latest-stable-on-ubuntu-20-04/14029/19

Common causes for Slicer crashing on linux are:

  • Mismatch between the OS OpenSSL version and 3D Slicer version. Check that OpenSSL 1.1.1g is available in the CMake options when you build it (it was added at some point, but not sure it was at 4.10.2)
  • Incompatibility with libffi (see indicated post).

I hope it helps. But as @lassoan mentioned, building old releases of Slicer in new OSs can be challenging. You would be better off migrating to recent OS and Slicer versions.