Troubleshooting

General troubleshooting tips

• If you ran into a problem with the above steps, after fixing the

problem you can type Pkg.build() to try to rerun the install scripts.

• If you tried it a while ago, try running Pkg.update() and try again: this will fetch the latest versions of the Julia packages in case the problem you saw was fixed. Run Pkg.build("IJulia") if your Julia version may have changed. If this doesn't work, you could try just deleting the whole .julia directory in your home directory (on Windows, it is called Users\USERNAME\.julia in your home directory) via rm(Pkg.dir(),recursive=true) in Julia and re-adding the packages.
• On MacOS, you currently need MacOS 10.7 or later; MacOS 10.6 doesn't work (unless you compile Julia yourself, from source code).
• Internet Explorer 8 (the default in Windows 7) or 9 don't work with the notebook; use Firefox (6 or later) or Chrome (13 or later). Internet Explorer 10 in Windows 8 works (albeit with a few rendering glitches), but Chrome or Firefox is better.
• If the notebook opens up, but doesn't respond (the input label is In[*] indefinitely), try creating a new Python notebook (not Julia) from the New button in the Jupyter dashboard, to see if 1+1 works in Python. If it is the same problem, then probably you have a firewall running on your machine (this is common on Windows) and you need to disable the firewall or at least to allow the IP address 127.0.0.1. (For the Sophos endpoint security software, go to "Configure Anti-Virus and HIPS", select "Authorization" and then "Websites", and add 127.0.0.1 to "Authorized websites"; finally, restart your computer.) If the Python test works, then IJulia may not be installed in the global or default environment and you may need to install a custom Julia kernel that uses your required Project.toml (see Julia projects).
• Try running jupyter --version and make sure that it prints 3.0.0 or larger; earlier versions of IPython are no longer supported by IJulia.
• You can try setting ENV["JUPYTER"]=""; Pkg.build("IJulia") to force IJulia to go back to its own Conda-based Jupyter version (if you previously tried a different jupyter).

Debugging IJulia problems

If IJulia is crashing (e.g. it gives you a "kernel appears to have died" message), you can modify it to print more descriptive error messages to the terminal by doing:

ENV["IJULIA_DEBUG"]=true
Pkg.build("IJulia")

Restart the notebook and look for the error message when IJulia dies. (This changes IJulia to default to verbose = true mode, and sets capture_stderr = false, hopefully sending a bunch of debugging to the terminal where you launched jupyter).

When you are done, set ENV["IJULIA_DEBUG"]=false and re-run Pkg.build("IJulia") to turn off the debugging output.