I have used BrainNet Viewer before and have merged meshes many times

I have new Mac (Monterey 12.1) and installed BNV recently. When I try to load the *.pial Freesurfer files to merge meshes, it does not allow me to select the *.pial files. The only files it reads are *.nv files.

Do you know what might be happening?

Thanks a lot!
Elena