Brian,
I realize that this particular computer is old. But I still feel like it’s fixable (and hopefully without paying apple a fortune to do it) , please let me know if I’m wrong.
I have a 2012 series MacBook Pro. It was my main editing device up until this year. It started running extremely slow on me. I mean upwards of 20 minutes to even move from the login screen once entering my password, slow. I tried everything I could think of on my own, but it was almost impossible as it was just too lagging to do anything. I contacted apple support, they walked me through a ton of steps that I couldn’t tell you now, but they helped me to delete things that I didn’t know needed to be deleted and had never done in 6 years ( there was over 800,000 files ) and cleared a bunch of other things as well. It did nothing. Nothing at all. I ended up taking it in to be looked at, there was some malware? I think it was they called it, they got it off, and it went from about 20 min lag to a 18 min lag. They ended up replacing a hard robe cable, something about that years harddrive has movable parts and my cable was ruined. (It’s been out of commission for 5 weeks at this point) I was told it would be checked before getting it back. I can only assume that it wasn’t since it still wasn’t working properly. I took it back in, and ended up buying a new one as I was now almost 7 weeks behind on editing... I would however still like to have this computer as a back up if needed, if it’s possible. I will try to attach all the work order from apple so you know what they did. Thanks for your help!