Brtdku

I've been using Jupyter Notebook 4.5 (Anaconda distribution) for a while. And today I tried to upgrade it to 5 using conda upgrade notebook. After a little while it was done (many packages were downloaded and updated). But I immediately got a '500 internal error'. Then I pip upgraded my nbconvert as suggested by some thread on the sub. But now my kernel can't start.

The error I get from my cmd:

ERROR:tornado.application:Exception in callback (<zmq.sugar.socket.Socket object

 at 0x0000000004E03B40>, <function wrap.<locals>.null_wrapper at 0x0000000004E43

400>)

Traceback (most recent call last):

  File "C:UsersbliuAppDataLocalContinuumAnaconda3libsite-packagestornad

oioloop.py", line 887, in start

    handler_func(fd_obj, events)

  File "C:UsersbliuAppDataLocalContinuumAnaconda3libsite-packagestornad

ostack_context.py", line 275, in null_wrapper

    return fn(*args, **kwargs)

  File "C:UsersbliuAppDataLocalContinuumAnaconda3libsite-packageszmqev

entloopzmqstream.py", line 450, in _handle_events

    self._handle_recv()

  File "C:UsersbliuAppDataLocalContinuumAnaconda3libsite-packageszmqev

entloopzmqstream.py", line 480, in _handle_recv

    self._run_callback(callback, msg)

  File "C:UsersbliuAppDataLocalContinuumAnaconda3libsite-packageszmqev

entloopzmqstream.py", line 432, in _run_callback

    callback(*args, **kwargs)

  File "C:UsersbliuAppDataLocalContinuumAnaconda3libsite-packagestornad

ostack_context.py", line 275, in null_wrapper

    return fn(*args, **kwargs)

  File "C:UsersbliuAppDataLocalContinuumAnaconda3libsite-packagesipyker

nelkernelbase.py", line 276, in dispatcher

    return self.dispatch_shell(stream, msg)

  File "C:UsersbliuAppDataLocalContinuumAnaconda3libsite-packagesipyker

nelkernelbase.py", line 226, in dispatch_shell

    self.pre_handler_hook()

  File "C:UsersbliuAppDataLocalContinuumAnaconda3libsite-packagesipyker

nelkernelbase.py", line 241, in pre_handler_hook

    self.saved_sigint_handler = signal(SIGINT, default_int_handler)

  File "C:UsersbliuAppDataLocalContinuumAnaconda3libsignal.py", line 47,

 in signal

    handler = _signal.signal(_enum_to_int(signalnum), _enum_to_int(handler))

ValueError: signal only works in main thread

I tried to upgrade my ipykernel but got this error message:

Cannot uninstall 'ipykernel'. It is a distutils installed project and thus we ca

nnot accurately determine which files belong to it which would lead to only a pa

rtial uninstall.

Problem fixed.

Just found the solution:

The reason was that my tornado version was still 4.2 but the new Jupyter requires 5.1. Unable to update tornado directly, I just reinstalled Jupyter Notebook:

conda uninstall jupyter tornado

conda install jupyter