Segmentation Fault using covar?

Hi!

This is a bug in GROMACS 2023. You can use GROMACS 2022.5 instead or use the workaround described here: Gromacs 2023: Segmentation fault with gmx anaeig (but no problem with Gromacs 2022.4) - #4 by al42and.

The bug will be fixed in GROMACS 2023.1, to be released by the end of April.