# Jupyter Notebook "stalling" on Windows 10

**URL:** <https://discourse.jupyter.org/t/jupyter-notebook-stalling-on-windows-10/20483>\
**Category:** Notebook\
**Created:** [July 19, 2023, 11:46am UTC](https://discourse.jupyter.org/t/jupyter-notebook-stalling-on-windows-10/20483 "2023-07-19T11:46:48Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![mikecro](https://avatars.discourse-cdn.com/v4/letter/m/74df32/32.png) [@mikecro](https://discourse.jupyter.org/u/mikecro)\
**Post date:** [July 19, 2023, 11:46am UTC](https://discourse.jupyter.org/t/jupyter-notebook-stalling-on-windows-10/20483/1 "2023-07-19T11:46:48Z")

</div>

As of 1-2 weeks ago, a notebook I am developing has started to pause in mid flow. It is not in a compute-intensive step and there appears to be no pattern as to where is pauses.  
By pause I mean the current step has In [\*]

I am getting some console output which has errors (see below)  
I am now fully up to date on packages but the error started before I updated all

Thank you

```auto
Exception in callback None()
handle: <Handle cancelled>
Traceback (most recent call last):
  File "C:\Users\<user>\AppData\Local\Programs\Python\Python311\Lib\asyncio\events.py", line 80, in _run
    self._context.run(self._callback, *self._args)
  File "C:\Users\<user>\AppData\Roaming\Python\Python311\site-packages\tornado\platform\asyncio.py", line 192, in _handle_events
    handler_func(fileobj, events)
  File "C:\Users\<user>\AppData\Roaming\Python\Python311\site-packages\tornado\iostream.py", line 695, in _handle_events
    self._handle_write()
  File "C:\Users\<user>\AppData\Roaming\Python\Python311\site-packages\tornado\iostream.py", line 965, in _handle_write
    self._write_buffer.advance(num_bytes)
  File "C:\Users\<user>\AppData\Roaming\Python\Python311\site-packages\tornado\iostream.py", line 182, in advance
    assert 0 < size <= self._size
           ^^^^^^^^^^^^^^^^^^^^^^
AssertionError
[I 11:47:52.453 NotebookApp] Starting buffering for 130b71b0-f5db-4413-a8b6-c5d5dc141e96:aa6db31b0af84030a8909fbeee721522
[I 11:47:53.836 NotebookApp] Restoring connection for 130b71b0-f5db-4413-a8b6-c5d5dc141e96:aa6db31b0af84030a8909fbeee721522
[I 11:47:53.836 NotebookApp] Replaying 80 buffered messages
[I 11:49:46.565 NotebookApp] Saving file at /<company>/<division>/Python/Production 2023 v13-Copy1.ipynb
[I 11:51:46.575 NotebookApp] Saving file at /<company>/<division>/Python/Production 2023 v13-Copy1.ipynb
[I 11:55:46.577 NotebookApp] Saving file at /<company>/<division>/Python/Production 2023 v13-Copy1.ipynb

```

---

<div class="post-metadata">

**Author:** ![mikecro](https://avatars.discourse-cdn.com/v4/letter/m/74df32/32.png) [@mikecro](https://discourse.jupyter.org/u/mikecro)\
**Post date:** [July 20, 2023, 8:46am UTC](https://discourse.jupyter.org/t/jupyter-notebook-stalling-on-windows-10/20483/2 "2023-07-20T08:46:27Z")

</div>

I have seen advice to rollback tornado. What version should I rollback to? Currently on 6.3.2

I need to stay on pip and not move to Anaconda as suggested elsewhere. Full listing below.

Package Version

* * *

anyio 3.7.1  
argon2-cffi 21.3.0  
argon2-cffi-bindings 21.2.0  
arrow 1.2.3  
asttokens 2.2.1  
attrs 23.1.0  
backcall 0.2.0  
beautifulsoup4 4.12.2  
bleach 6.0.0  
cffi 1.15.1  
colorama 0.4.6  
comm 0.1.3  
debugpy 1.6.7  
decorator 5.1.1  
defusedxml 0.7.1  
entrypoints 0.4  
et-xmlfile 1.1.0  
executing 1.2.0  
fastjsonschema 2.17.1  
fqdn 1.5.1  
greenlet 2.0.2  
idna 3.4  
ipykernel 6.24.0  
ipython 8.14.0  
ipython-genutils 0.2.0  
isoduration 20.11.0  
jedi 0.18.2  
Jinja2 3.1.2  
jsonpointer 2.4  
jsonschema 4.17.3  
jupyter\_client 8.3.0  
jupyter\_core 5.3.1  
jupyter-events 0.6.3  
jupyter\_server 2.7.0  
jupyter\_server\_terminals 0.4.4  
jupyterlab-pygments 0.2.2  
MarkupSafe 2.1.1  
matplotlib-inline 0.1.6  
mistune 3.0.1  
nbclassic 1.0.0  
nbclient 0.8.0  
nbconvert 7.7.2  
nbformat 5.9.1  
nest-asyncio 1.5.6  
notebook 6.5.4  
notebook\_shim 0.2.3  
numpy 1.25.1  
openpyxl 3.1.2  
overrides 7.3.1  
packaging 23.1  
pandas 2.0.3  
pandocfilters 1.5.0  
parso 0.8.3  
pickleshare 0.7.5  
pip 23.2  
platformdirs 3.9.1  
prometheus-client 0.17.1  
prompt-toolkit 3.0.39  
psutil 5.9.5  
pure-eval 0.2.2  
pycparser 2.21  
Pygments 2.15.1  
pyodbc 4.0.39  
pyrsistent 0.19.3  
python-dateutil 2.8.2  
python-json-logger 2.0.4  
pytz 2023.3  
pywin32 306  
pywinpty 2.0.11  
PyYAML 6.0.1  
pyzmq 25.1.0  
rfc3339-validator 0.1.4  
rfc3986-validator 0.1.1  
Send2Trash 1.8.2  
setuptools 68.0.0  
six 1.16.0  
sniffio 1.3.0  
soupsieve 2.4.1  
SQLAlchemy 2.0.19  
stack-data 0.6.2  
terminado 0.17.1  
tinycss2 1.2.1  
tornado 6.3.2  
traitlets 5.9.0  
typing\_extensions 4.7.1  
tzdata 2023.3  
uri-template 1.3.0  
wcwidth 0.2.6  
webcolors 1.13  
webencodings 0.5.1  
websocket-client 1.6.1