Well they fixed fast user switching!

[rezwits]

They fixed fast user switching with 10.12.1

For Network Accounts and Local Accounts!

You can login with 2nd account and logout successfully.

THANKS!

 

[rweed]

Congrats. Now if I could only log in to more than 6 accounts under Sierra using fast user switching.

 

[Ritsuka]

see this: http://krypted.com/mac-os-x/maximum-files-in-mac-os-x/