I had bought a new MacBook Air to replace my ancient MacBook Pro, and it arrived as I was heading out of town. I left my old MBP behind and stopped by the Apple Store to pickup my new MBA.
As soon as I got to the hotel, I setup my MBA via my iCloud account. All my documents are backed up in iCloud and so is my Desktop. Restoring from iCloud got my Mac about 90% of the way there. Which meant the last 10% will take up the other 90% of the time.
Some things had to be manually setup. My email accounts (even though they’re all in my iPhone and iPad), my messages (you have to go into the iPhone and select to share messages on your new system, and 1Paaword.
I got home, and used my TimeMachine backup to restore my settings. Unfortunately, it overrode setting I had. My new machine got my old machine name. My desktop folder ended up with two copies of everything.
However, the worst was 1Password. 1Password wouldn’t let me log in. It kept telling me I was using the wrong password.
I was using the right password. I could log into 1Password.com, my iPad, my iPhone, and my old MBP. My However, MBA insisted my password was wrong.
I tried deleting and redownloading 1Password, I tried various things in 1Password.com, but nothing worked.
I contacted 1Password. It turns out that there’s a Data folder inside $HOME/Library that had some information in it that prevented me from logging in only on this machine.
One of the issues with MacOS is that removing an app doesn’t necessarily clean things up. In Windows, removing an app has to be done in the Control Panel or System Settings. However, programs track all the folders and files placed on your system in Windows and thoroughly clean it out. That doesn’t happen on the Mac. You can use one of the many app cleaners, but there’s nothing official.