Jupyter lab run_kernel not working

cpf-work
Fri, 26 Sep 2025 08:59:43 +0000
Jupyter-Notebook

I finally decided to update to 1.11 and juliaup. So I installed 1.11 with juliaup and got rid of the former 1.9 version I used. Ì’m on Windows 11. Everything seemed working except jupyterlab. I get the following in the terminal from which I started jupyter lab:

ERROR: UndefVarError: `run_kernel` not defined in `IJulia`
Suggestion: check for spelling errors or missing imports.
Stacktrace:
 [1] getproperty(x::Module, f::Symbol)
   @ Base .\Base.jl:42
 [2] top-level scope
   @ none:1

I started digging a bit and looked in the kernel.json where it seems the following is executed

import IJulia; IJulia.run_kernel()"

So I tried this in the repl and I get

Starting kernel event loops.
connect ipython with --existing C:\WINDOWS\System32/profile-15844.json
ERROR: SystemError: opening file "profile-15844.json": Permission denied
Stacktrace:
  [1] systemerror(p::String, errno::Int32; extrainfo::Nothing)
    @ Base .\error.jl:176
  [2] systemerror
    @ .\error.jl:175 [inlined]
  [3] open(fname::String; lock::Bool, read::Nothing, write::Nothing, create::Nothing, truncate::Bool, append::Nothing)
    @ Base .\iostream.jl:295
  [4] open
    @ .\iostream.jl:277 [inlined]
  [5] open(fname::String, mode::String; lock::Bool)
    @ Base .\iostream.jl:358
  [6] open(fname::String, mode::String)
    @ Base .\iostream.jl:357
  [7] open(::IJulia.var"#26#28"{IJulia.Kernel}, ::String, ::Vararg{String}; kwargs::@Kwargs{})
    @ Base .\io.jl:408
  [8] open
    @ .\io.jl:407 [inlined]
  [9] init(args::Vector{String}, kernel::IJulia.Kernel, profile::Nothing)
    @ IJulia C:\Users\m129319\.julia\packages\IJulia\GFGaR\src\init.jl:81
 [10] init
    @ C:\Users\m129319\.julia\packages\IJulia\GFGaR\src\init.jl:67 [inlined]
 [11] run_kernel()
    @ IJulia C:\Users\m129319\.julia\packages\IJulia\GFGaR\src\kernel.jl:11
 [12] top-level scope
    @ REPL[2]:1

I found the Windows\System32 fishy and found a thread where it’s mentioned this is not the correct behaviour, but no real solution. A bit more reading suggested to me it has something to do with environments etc. I finally changed

"--project=@.",

in kernel.json to

"--project=C:\\Users\\XXmyusernameXX\\.julia\\environments\\v1.11",

(with the correct username of course) and now everything is working. However, I find this to be a bit of a hack and not so nice. Interestingly, when I open a fresh repl and check the project everything seems fine?

julia> Base.active_project()
"C:\\Users\\m129319\\.julia\\environments\\v1.11\\Project.toml"

I think there’s some kind of issue here but I’m not sure where to open a respective issue. IJulia? jupyter?

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