Uncaught AttributeError: 'NoneType' object has no attribute 'cursor'

[peter-shr]

Steps to reproduce

1. First
2. Second
3. Third

Traceback (most recent call last):
  File "C:/Users/user/.qgis2/python/plugins\quickfinder\gui\refresh_dialog.py", line 119, in refresh
    self.project_finder.optimize()
  File "C:/Users/user/.qgis2/python/plugins\quickfinder\core\project_finder.py", line 290, in optimize
    cur = self.conn.cursor()
AttributeError: 'NoneType' object has no attribute 'cursor'

quickfinder 3.3.0, QGIS 2.14.7-Essen on Windows 10