I’ve done two migrations from old computers to new ones in the last week, and both of them ended up with permissions problems after the process was done. What happened was that nothing seemed to be working properly afterward, and the computers would get stuck in an endless loop of an error message saying “macOS needs to repair your Library,”.
Typing in the password (or using Touch ID) to allow the “repair” did no good, and each computer was pretty much useless with constant warning pop-ups. When I checked the permissions on one machine, I found that my user’s folders—Desktop, Documents, and so on—were owned by root. If you know anything about the underpinnings of macOS, then…well…you know that’s just bad. I can’t remember the last time I had such an “oh holy crap” feeling in my stomach.
If you start having this problem, Apple does have a support article on what to do, which involves using your Home folder’s “Get Info” window to propagate the proper permissions. (Say that three times fast.)
Read more at the MacObserver.com