Where did my repositories go? They were along the left side of Sourcetree, now it is blank and I don't know how to find them. See the screenshot:
version 2.0+
Bookmarks have changed to local repository folders and are viewed as tabs.
Click the + icon beside the tabs to open a new tab. Your repositories/bookmarks will show up there.
before version 2.0
These are actually "bookmarks" for your repositories that you have lost.
To open them backup, click View > Show/Hide Bookmarks, or press CTRL + B.
You might also have just hidden them by accidentally collapsing them to the left. Just drag the bar over, see: