Sublime Text 3 build 3103 on openSuSE 42.1
The problem occurs frequently, but not always, when I have one project open and open a second (pre-existing) project either via “Project > Open Project” or “Project > Open Recent” menu selections.
As expected, a new window opens for the second project, the project directory tree is displayed in the sidebar and any previously-open files are opened. Then the UI freezes, frequently with spinner icons on one or more subdirectories in the project directory tree. The UI is now frozen in both project windows. On one occasion I left things in this state over a lunch hour to see if it would recover, but it did not.
If I then kill sublime text and attempt to restart it, the window opens with a black background and the application is completely unresponsive.
To make sublime text functional again I must delete the file
“~/.config/sublime-text-3/Local/Auto Save Session.sublime_session”
before restarting the application.