[FIXED] Kernel Error using Julia on Jupyter Notebook

Issue

Hi so I'm quite new with using Julia and Notebook. When I first downloaded Julia, everything worked great, but then suddenly the kernel said it was dead and I couldn't get it to work again (restarted and tried reinstalling)

I ended up downloading a newer version of Julia (1.4.1 to 1.4.2), but that didn't seem to help. Now however, instead of the kernel being dead, there is an error, and I unfortunately have no idea what it means or how to fix it.

I want to preface this by saying that I accidentally deleted the conda folder in my C drive that notebook needed without realizing what it was, but I had thought it reinstalled through Julia, I dont know if that makes a difference or not. Additionally, I had to use python for my school, but deleted it since I don't need it anymore, so I'm unsure of if that has an effect (since I'm aware that notebook uses python stuff)

The error is as follows:

Traceback (most recent call last):

File "C:\Users\Adam\.julia\conda\3\lib\site-packages\tornado\web.py", line 1703, in _execute
    result = await result

File "C:\Users\Adam\.julia\conda\3\lib\site-packages\tornado\gen.py", line 742, in run
    yielded = self.gen.throw(*exc_info)  # type: ignore

File "C:\Users\Adam\.julia\conda\3\lib\site-packages\notebook\services\sessions\handlers.py", line 72, in post
    type=mtype))


File "C:\Users\Adam\.julia\conda\3\lib\site-packages\tornado\gen.py", line 735, in run
    value = future.result()

File "C:\Users\Adam\.julia\conda\3\lib\site-packages\tornado\gen.py", line 742, in run
    yielded = self.gen.throw(*exc_info)  # type: ignore

File "C:\Users\Adam\.julia\conda\3\lib\site-packages\notebook\services\sessions\sessionmanager.py", line 88, in create_session
    kernel_id = yield self.start_kernel_for_session(session_id, path, name, type, kernel_name)

File "C:\Users\Adam\.julia\conda\3\lib\site-packages\tornado\gen.py", line 735, in run
    value = future.result()

File "C:\Users\Adam\.julia\conda\3\lib\site-packages\tornado\gen.py", line 742, in run
    yielded = self.gen.throw(*exc_info)  # type: ignore

File "C:\Users\Adam\.julia\conda\3\lib\site-packages\notebook\services\sessions\sessionmanager.py", line 101, in start_kernel_for_session
    self.kernel_manager.start_kernel(path=kernel_path, kernel_name=kernel_name)

File "C:\Users\Adam\.julia\conda\3\lib\site-packages\tornado\gen.py", line 735, in run
    value = future.result()

File "C:\Users\Adam\.julia\conda\3\lib\site-packages\tornado\gen.py", line 209, in wrapper
    yielded = next(result)

File "C:\Users\Adam\.julia\conda\3\lib\site-packages\notebook\services\kernels\kernelmanager.py", line 168, in start_kernel
    super(MappingKernelManager, self).start_kernel(**kwargs)

File "C:\Users\Adam\.julia\conda\3\lib\site-packages\jupyter_client\multikernelmanager.py", line 158, in start_kernel
    km.start_kernel(**kwargs)

File "C:\Users\Adam\.julia\conda\3\lib\site-packages\jupyter_client\manager.py", line 305, in start_kernel
    self.kernel = self._launch_kernel(kernel_cmd, **kw)

File "C:\Users\Adam\.julia\conda\3\lib\site-packages\jupyter_client\manager.py", line 212, in _launch_kernel
    return launch_kernel(kernel_cmd, **kw)

File "C:\Users\Adam\.julia\conda\3\lib\site-packages\jupyter_client\launcher.py", line 135, in launch_kernel
    proc = Popen(cmd, **kwargs)

File "C:\Users\Adam\.julia\conda\3\lib\subprocess.py", line 800, in __init__
    restore_signals, start_new_session)

File "C:\Users\Adam\.julia\conda\3\lib\subprocess.py", line 1207, in _execute_child
    startupinfo)

FileNotFoundError: [WinError 2] The system cannot find the file specified

Thank you in advance to anyone who can help me.

Solution

By default, IJulia should install its own Miniconda, so you fiddling with a separate Python installation shouldn't hurt.

The first port of call when you can't get the notebook server to run is always to re-run the build script, which is run when you first install IJulia. Enter the REPL package mode by pressing ] and run build IJulia. This should reinstall dependencies as necessary, and re-register the kernel of the Julia version you're in with Jupyter.

Answered By - Nils Gudat