So I am running El Capitan on my Mac Pro 1,1 without issue. Recently, I had a mail problem where it had trouble connecting to my comcast server. I managed to fix that, but then when I went to open my messages, I could see the headers but the messages themselves were blank. I tried to rebuild and that did not work. I tried to remove the envelope index file to reimport, and it did, but not the inbox. However, the new mail I received I was able to read just fine. I put the old files back in and my mail reappeared but so did the old problem of having blank messages. I did a rebuild again and got the beach ball. When I relaunched mail, my inbox was gone. Completely empty. As if the system had deleted everything. So... Did it delete everything? Am I screwed? I had thousands of messages in there... I do have a backup from 2017 that could restore a lot of them on an external drive. I am not sure how to reimport those files into my mail if I need to. I'd rather get ALL my messages and not just the ones from 2017, but I don't know how to do either. Any suggestions?