Pycharm console cannot connect after update

A patch has been committed on GitHub (https://github.com/JetBrains/intellij-community/commit/d9f32f650b5a1f4e7a9646011da415d27e18a210)

You can also apply the patch your self, file path:

<PyCharm Root>/helpers/pydev/_pydev_bundle/pydev_ipython_console_011.py

Modify:

     class PyDevIPCompleter(IPCompleter):

     def __init__(self, *args, **kwargs):
         """ Create a Completer that reuses the advanced completion support of PyDev
             in addition to the completion support provided by IPython """
         IPCompleter.__init__(self, *args, **kwargs)
         # Use PyDev for python matches, see getCompletions below
-        self.matchers.remove(self.python_matches)
+        if self.python_matches in self.matchers:
+            # `self.python_matches` matches attributes or global python names
+            self.matchers.remove(self.python_matches)

i found that ipython is the problem ipython(6.3.0) was updated but you should downgrade to ipython (6.2.0) if you want to use pycharm now