I put a new browser on a new drive, and installed the new Firefox. When the new Firefox went to automatic update, it updated an earlier version. The updated version will not run on the os on that drive. So I downloaded the original version that I had, but it won't start because it cant find a profile. Well the old profile is there, in the user library firefox folder as it should be. Many passwords and preferences are stored on that profile. I could redo everything manually, but if I could access that profile it sure would be easier. Old browser was 78.15.0 for 10.11.6 new one in the trash... requires 10.12... thanks, Chuck