Board Thread:Support Requests - Getting Technical/@comment-29648874-20170212163112/@comment-168424-20170215183627

The best way to get some clues would be to open up the Javascript console in Chrome or Firefox (or Show Error console, if you have the Safari Develop menu enabled) and look for errors when you try to use comments, etc.

It's unlikely that the OS is the problem. I use the older Mavericks (10.9) on my Mac and have never seen a problem like this.