The problems just keep getting worse. Original problem (I guess)
So I restored (from a CCC clone) after installing macOS Sierra from install macOS Sierra.app while my computer was booting from a 2013 Macbook Air (borrowed computer) connected via firewire (in target disk mode), since I really needed my computer to work at school.
Finder semi-crashes constantly now, it's actually worse off then when I started.
50% of the time when I try to scroll up or down in finder, it crashes.
I know I should just move everything over manually and find out what the problem is, but I don't have time for that, it could take several days since I have almost a terabite of data to go through.
Not to mention that I'd have to reinstall a bunch of drivers and applications because they can't be moved over (I'm not so bothered by that though).
I'm looking for any way to make my computer run macOS properly temporarily, just until I have enough time (a couple of days) to go through everything.
Fixing it would be great too, I'm going to try reinstalling macOS from new recovery partition, but I don't expect that to help for long.
Please tell me if finder logs would be helpful.
My macbook pro: mid-2012, 1tb macOS ssd instead of superdrive, 500gb windows hdd in hdd slot, 16gb ram, dying cheap battery from Newegg, SIP disabled.
OS has some modifications I think, I'll add what apps I used for that when I can.
I tried to screen record finder saying nothing exists, but QuickTime quit as soon as it happens.
Thanks @Allan for all of the help before, but I think that this may be a different problem.