# Error: IOError: symlink: operation not permitted (EPERM)

**URL:** https://discourse.julialang.org/t/error-ioerror-symlink-operation-not-permitted-eperm/119872
**Category:** New to Julia
**Created:** [September 25, 2024, 2:29pm UTC](https://discourse.julialang.org/t/error-ioerror-symlink-operation-not-permitted-eperm/119872 "2024-09-25T14:29:35Z")
**Posts on this page:** 5
**Page:** 1

<div class="post-metadata">

### Author: ![Jesper\_Keijser](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jesper_keijser/32/212232_2.png) [@Jesper\_Keijser](https://discourse.julialang.org/u/Jesper_Keijser)
#### Post date: [September 25, 2024, 2:29pm UTC](https://discourse.julialang.org/t/error-ioerror-symlink-operation-not-permitted-eperm/119872/1 "2024-09-25T14:29:35Z")

</div>

Hello,  
Pretty new to julia, have used it ever so often for school work the last few years, but not very familiar at all. When running the code below I get the error posted below. It is mainly the error stated in the title that I need help with, as I think the first error has to do with my code, but feel free to correct that as well.

Not very familiar with stacktraces and dictionaries, so explain as if I was a 5 year old. Thank you:)

The main file:

```julia
using JuMP
import Ipopt

include("data.jl")

model = Model(Ipopt.Optimizer)

# Voltage amplitude at each node
@variable(model, 0.98 <= v[n in nodes] <= 1.02)

# Voltage phase angle at each node
@variable(model, -pi <= θ[n in nodes] <= pi)

# Active power generation
@variable(model, 0 <= P_G[i in generators] <= P_G_max[i])

# Reactive power generation (limited to ±3% of max capacity)
@variable(model, Q_G[i in generators],
    lower_bound = -0.03 * P_G_max[i],
    upper_bound = 0.03 * P_G_max[i]
)

# Active power flow from node k to l
@variable(model, p[(k, l) in edges])

# Reactive power flow from node k to l
@variable(model, q[(k, l) in edges])

@objective(model, Min, sum(costs[i] * P_G[i] for i in generators))

# Active power flow equations
for (k, l) in edges
    g = gkl[(k, l)]
    b = bkl[(k, l)]
    @NLconstraint(model,
        p[(k, l)] == v[k]^2 * g -
                     v[k] * v[l] * (g * cos(θ[k] - θ[l]) + b * sin(θ[k] - θ[l]))
    )
end

# Reactive power flow equations
for (k, l) in edges
    g = gkl[(k, l)]
    b = bkl[(k, l)]
    @NLconstraint(model,
        q[(k, l)] == -v[k]^2 * b -
                      v[k] * v[l] * (g * sin(θ[k] - θ[l]) - b * cos(θ[k] - θ[l]))
    )
end

for n in nodes
    # Total active power generated at node n
    P_G_node = sum(P_G[i] for i in keys(generators) if generators[i] == n)
    
    # Active power demand at node n
    D_n = demand_at_node[n]
    
    # Net active power flow (incoming - outgoing)
    incoming_p = sum(p[(k, n)] for k in neighbors[n] if (k, n) in edges)
    outgoing_p = sum(p[(n, k)] for k in neighbors[n] if (n, k) in edges)
    
    @constraint(model, P_G_node - D_n + incoming_p - outgoing_p == 0)
end

for n in nodes
    # Total reactive power generated at node n
    Q_G_node = sum(Q_G[i] for i in keys(generators) if generators[i] == n)
    
    # Net reactive power flow (incoming - outgoing)
    incoming_q = sum(q[(k, n)] for k in neighbors[n] if (k, n) in edges)
    outgoing_q = sum(q[(n, k)] for k in neighbors[n] if (n, k) in edges)
    
    @constraint(model, Q_G_node + incoming_q - outgoing_q == 0)
end

optimize!(model)

```

using tha data in the file below.

```julia
nodes = 1:11

# Edges between nodes
edges = [
    (1, 2),
    (1, 11),
    (2, 3),
    (2, 11),
    (3, 4),
    (3, 9),
    (4, 5),
    (5, 6),
    (5, 8),
    (6, 7),
    (7, 8),
    (7, 9),
    (8, 9),
    (9, 10),
    (10, 11)
]

# Parameters for each edge 
bkl_values = [-20.1, -22.3, -16.8, -17.2, -11.7, -19.4, -10.8, -12.3, -9.2, -13.9, -8.7, -11.3, -7.7, -13.5, -26.7]
gkl_values = [4.12, 5.67, 2.41, 2.78, 1.98, 3.23, 1.59, 1.71, 1.26, 1.11, 1.32, 2.01, 4.41, 2.14, 5.06]

# Create dictionaries mapping edges to their parameters
bkl = Dict(edges[i] => bkl_values[i] for i in 1:length(edges))
gkl = Dict(edges[i] => gkl_values[i] for i in 1:length(edges))

# Generators and their nodes
generators = Dict(
    1 => 2,
    2 => 2,
    3 => 2,
    4 => 3,
    5 => 4,
    6 => 5,
    7 => 7,
    8 => 9,
    9 => 9
)

# Maximum capacities 
P_G_max = Dict(
    1 => 0.02,
    2 => 0.15,
    3 => 0.08,
    4 => 0.07,
    5 => 0.04,
    6 => 0.17,
    7 => 0.17,
    8 => 0.26,
    9 => 0.05
)

# Production costs 
costs = Dict(
    1 => 175,
    2 => 100,
    3 => 150,
    4 => 150,
    5 => 300,
    6 => 350,
    7 => 400,
    8 => 300,
    9 => 200
)

# Consumers and their nodes
consumers = Dict(
    1 => 1,
    2 => 4,
    3 => 6,
    4 => 8,
    5 => 9,
    6 => 10,
    7 => 11
)

# Demands 
D_k = Dict(
    1 => 0.10,
    2 => 0.19,
    3 => 0.11,
    4 => 0.09,
    5 => 0.21,
    6 => 0.05,
    7 => 0.04
)

# Map demands to nodes
demand_at_node = Dict(n => 0.0 for n in nodes)
for (c, n) in consumers
    demand_at_node[n] += D_k[c]
end

# Initialize neighbor dictionary
neighbors = Dict(n => Int[] for n in nodes)

# Populate neighbors for undirected edges
for (k, l) in edges
    push!(neighbors[k], l)
    push!(neighbors[l], k)
end

```

produces the following stacktrace:

```julia
ERROR: KeyError: key 7 => 7 not found
Stacktrace:
 [1] getindex(::Dict{Int64,Float64}, ::Pair{Int64,Int64}) at .\dict.jl:477
 [2] (::var"#97#98")(::Pair{Int64,Int64}) at C:\Users\keijs\.julia\packages\JuMP\MnJQc\src\Containers\macro.jl:183
 [3] #28 at C:\Users\keijs\.julia\packages\JuMP\MnJQc\src\Containers\container.jl:85 [inlined]
 [4] iterate at .\generator.jl:47 [inlined]
 [5] collect(::Base.Generator{JuMP.Containers.VectorizedProductIterator{Tuple{Dict{Int64,Int64}}},JuMP.Containers.var"#28#29"{var"#97#98"}}) at .\array.jl:665
 [6] map(::Function, ::JuMP.Containers.VectorizedProductIterator{Tuple{Dict{Int64,Int64}}}) at .\abstractarray.jl:2098
 [7] container(::Function, ::JuMP.Containers.VectorizedProductIterator{Tuple{Dict{Int64,Int64}}}, ::Type{JuMP.Containers.DenseAxisArray}) at C:\Users\keijs\.julia\packages\JuMP\MnJQc\src\Containers\container.jl:85
 [8] container(::Function, ::JuMP.Containers.VectorizedProductIterator{Tuple{Dict{Int64,Int64}}}) at C:\Users\keijs\.julia\packages\JuMP\MnJQc\src\Containers\container.jl:65
 [9] top-level scope at C:\Users\keijs\.julia\packages\JuMP\MnJQc\src\macros.jl:79

caused by: IOError: symlink: operation not permitted (EPERM)
Stacktrace:
 [1] uv_error at .\libuv.jl:97 [inlined]
 [2] symlink(::String, ::String) at .\file.jl:958
 [3] probe_symlink_creation(::String) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\PlatformEngines.jl:132
 [4] unpack(::String, ::String; verbose::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\PlatformEngines.jl:994
 [5] download_verify_unpack(::String, ::String, ::String; tarball_path::Nothing, ignore_existence::Bool, force::Bool, verbose::Bool, quiet_download::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\PlatformEngines.jl:1170
 [6] download_artifact(::Base.SHA1, ::String, ::String; verbose::Bool, quiet_download::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Artifacts.jl:750
 [7] (::Pkg.Artifacts.var"#44#46"{Bool,Bool,Base.SHA1,String})() at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Artifacts.jl:890
 [8] with_show_download_info(::Pkg.Artifacts.var"#44#46"{Bool,Bool,Base.SHA1,String}, ::String, ::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Artifacts.jl:907
 [9] ensure_artifact_installed(::String, ::Dict{String,Any}, ::String; platform::Pkg.BinaryPlatforms.Platform, verbose::Bool, quiet_download::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Artifacts.jl:889
 [10] ensure_all_artifacts_installed(::String; platform::Pkg.BinaryPlatforms.Platform, pkg_uuid::Nothing, include_lazy::Bool, verbose::Bool, quiet_download::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Artifacts.jl:958
 [11] download_artifacts(::Pkg.Types.Context, ::Array{String,1}; platform::Pkg.BinaryPlatforms.Windows, verbose::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Operations.jl:609
 [12] download_artifacts(::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}; platform::Pkg.BinaryPlatforms.Windows, verbose::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Operations.jl:588
 [13] add(::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}, ::Array{Base.UUID,1}; preserve::Pkg.Types.PreserveLevel, platform::Pkg.BinaryPlatforms.Windows) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Operations.jl:1084
 [14] add(::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}; preserve::Pkg.Types.PreserveLevel, platform::Pkg.BinaryPlatforms.Windows, kwargs::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:159
 [15] add(::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:112
 [16] #add#27 at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:109 [inlined]
 [17] add at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:109 [inlined]
 [18] #add#24 at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:107 [inlined]
 [19] add at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:107 [inlined]
 [20] add(::String; kwargs::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:106
 [21] add(::String) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:106
 [22] top-level scope at REPL[1]:1

caused by: IOError: symlink: operation not permitted (EPERM)
Stacktrace:
 [1] uv_error at .\libuv.jl:97 [inlined]
 [2] symlink(::String, ::String) at .\file.jl:958
 [3] probe_symlink_creation(::String) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\PlatformEngines.jl:132
 [4] unpack(::String, ::String; verbose::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\PlatformEngines.jl:994
 [5] download_verify_unpack(::String, ::String, ::String; tarball_path::Nothing, ignore_existence::Bool, force::Bool, verbose::Bool, quiet_download::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\PlatformEngines.jl:1170
 [6] download_artifact(::Base.SHA1, ::String, ::String; verbose::Bool, quiet_download::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Artifacts.jl:750
 [7] (::Pkg.Artifacts.var"#44#46"{Bool,Bool,Base.SHA1,String})() at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Artifacts.jl:890
 [8] with_show_download_info(::Pkg.Artifacts.var"#44#46"{Bool,Bool,Base.SHA1,String}, ::String, ::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Artifacts.jl:907
 [9] ensure_artifact_installed(::String, ::Dict{String,Any}, ::String; platform::Pkg.BinaryPlatforms.Platform, verbose::Bool, quiet_download::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Artifacts.jl:889
 [10] ensure_all_artifacts_installed(::String; platform::Pkg.BinaryPlatforms.Platform, pkg_uuid::Nothing, include_lazy::Bool, verbose::Bool, quiet_download::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Artifacts.jl:958
 [11] download_artifacts(::Pkg.Types.Context, ::Array{String,1}; platform::Pkg.BinaryPlatforms.Windows, verbose::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Operations.jl:609
 [12] download_artifacts(::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}; platform::Pkg.BinaryPlatforms.Windows, verbose::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Operations.jl:588
 [13] add(::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}, ::Array{Base.UUID,1}; preserve::Pkg.Types.PreserveLevel, platform::Pkg.BinaryPlatforms.Windows) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Operations.jl:1084
 [14] add(::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}; preserve::Pkg.Types.PreserveLevel, platform::Pkg.BinaryPlatforms.Windows, kwargs::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:159
 [15] add(::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:112
 [16] #add#27 at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:109 [inlined]
 [17] add at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:109 [inlined]
 [18] #add#24 at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:107 [inlined]
 [19] add at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:107 [inlined]
 [20] add(::String; kwargs::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:106
 [21] add(::String) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:106
 [22] top-level scope at REPL[1]:1

caused by: IOError: symlink: operation not permitted (EPERM)
Stacktrace:
 [1] uv_error at .\libuv.jl:97 [inlined]
 [2] symlink(::String, ::String) at .\file.jl:958
 [3] probe_symlink_creation(::String) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\PlatformEngines.jl:132
 [4] unpack(::String, ::String; verbose::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\PlatformEngines.jl:994
 [5] download_verify_unpack(::String, ::String, ::String; tarball_path::Nothing, ignore_existence::Bool, force::Bool, verbose::Bool, quiet_download::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\PlatformEngines.jl:1170
 [6] download_artifact(::Base.SHA1, ::String, ::String; verbose::Bool, quiet_download::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Artifacts.jl:750
 [7] (::Pkg.Artifacts.var"#44#46"{Bool,Bool,Base.SHA1,String})() at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Artifacts.jl:890
 [8] with_show_download_info(::Pkg.Artifacts.var"#44#46"{Bool,Bool,Base.SHA1,String}, ::String, ::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Artifacts.jl:907
 [9] ensure_artifact_installed(::String, ::Dict{String,Any}, ::String; platform::Pkg.BinaryPlatforms.Platform, verbose::Bool, quiet_download::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Artifacts.jl:889
 [10] ensure_all_artifacts_installed(::String; platform::Pkg.BinaryPlatforms.Platform, pkg_uuid::Nothing, include_lazy::Bool, verbose::Bool, quiet_download::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Artifacts.jl:958
 [11] download_artifacts(::Pkg.Types.Context, ::Array{String,1}; platform::Pkg.BinaryPlatforms.Windows, verbose::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Operations.jl:609
 [12] download_artifacts(::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}; platform::Pkg.BinaryPlatforms.Windows, verbose::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Operations.jl:588
 [13] add(::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}, ::Array{Base.UUID,1}; preserve::Pkg.Types.PreserveLevel, platform::Pkg.BinaryPlatforms.Windows) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Operations.jl:1084
 [14] add(::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}; preserve::Pkg.Types.PreserveLevel, platform::Pkg.BinaryPlatforms.Windows, kwargs::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:159
 [15] add(::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:112
 [16] #add#27 at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:109 [inlined]
 [17] add at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:109 [inlined]
 [18] #add#24 at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:107 [inlined]
 [19] add at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:107 [inlined]
 [20] add(::String; kwargs::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:106
 [21] add(::String) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:106
 [22] top-level scope at REPL[1]:1

caused by: IOError: symlink: operation not permitted (EPERM)
Stacktrace:
 [1] uv_error at .\libuv.jl:97 [inlined]
 [2] symlink(::String, ::String) at .\file.jl:958
 [3] probe_symlink_creation(::String) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\PlatformEngines.jl:132
 [4] unpack(::String, ::String; verbose::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\PlatformEngines.jl:994
 [5] download_verify_unpack(::String, ::String, ::String; tarball_path::Nothing, ignore_existence::Bool, force::Bool, verbose::Bool, quiet_download::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\PlatformEngines.jl:1170
 [6] download_artifact(::Base.SHA1, ::String, ::String; verbose::Bool, quiet_download::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Artifacts.jl:750
 [7] (::Pkg.Artifacts.var"#44#46"{Bool,Bool,Base.SHA1,String})() at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Artifacts.jl:890
 [8] with_show_download_info(::Pkg.Artifacts.var"#44#46"{Bool,Bool,Base.SHA1,String}, ::String, ::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Artifacts.jl:907
 [9] ensure_artifact_installed(::String, ::Dict{String,Any}, ::String; platform::Pkg.BinaryPlatforms.Platform, verbose::Bool, quiet_download::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Artifacts.jl:889
 [10] ensure_all_artifacts_installed(::String; platform::Pkg.BinaryPlatforms.Platform, pkg_uuid::Nothing, include_lazy::Bool, verbose::Bool, quiet_download::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Artifacts.jl:958
 [11] download_artifacts(::Pkg.Types.Context, ::Array{String,1}; platform::Pkg.BinaryPlatforms.Windows, verbose::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Operations.jl:609
 [12] download_artifacts(::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}; platform::Pkg.BinaryPlatforms.Windows, verbose::Bool) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Operations.jl:588
 [13] add(::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}, ::Array{Base.UUID,1}; preserve::Pkg.Types.PreserveLevel, platform::Pkg.BinaryPlatforms.Windows) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\Operations.jl:1084
 [14] add(::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}; preserve::Pkg.Types.PreserveLevel, platform::Pkg.BinaryPlatforms.Windows, kwargs::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:159
 [15] add(::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:112
 [16] #add#27 at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:109 [inlined]
 [17] add at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:109 [inlined]
 [18] #add#24 at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:107 [inlined]
 [19] add at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:107 [inlined]
 [20] add(::String; kwargs::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:106
 [21] add(::String) at D:\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.4\Pkg\src\API.jl:106
 [22] top-level scope at REPL[1]:1

```

Grateful for any help!

---

<div class="post-metadata">

### Author: ![nhz2](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nhz2/32/44428_2.png) [@nhz2](https://discourse.julialang.org/u/nhz2)
#### Post date: [September 25, 2024, 2:56pm UTC](https://discourse.julialang.org/t/error-ioerror-symlink-operation-not-permitted-eperm/119872/2 "2024-09-25T14:56:37Z")

</div>

Hello and welcome to the Julia discourse.

I think the issue is that you are running Julia 1.4. Updating to Julia 1.10.5 [Download Julia](https://julialang.org/downloads/) should fix the symlink error.

---

<div class="post-metadata">

### Author: ![Jesper\_Keijser](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jesper_keijser/32/212232_2.png) [@Jesper\_Keijser](https://discourse.julialang.org/u/Jesper_Keijser)
#### Post date: [September 25, 2024, 6:31pm UTC](https://discourse.julialang.org/t/error-ioerror-symlink-operation-not-permitted-eperm/119872/3 "2024-09-25T18:31:32Z")

</div>

It solved the symblink problem. The keyError remains though.

```julia
ERROR: KeyError: key 5 => 4 not found
Stacktrace:
  [1] getindex(h::Dict{Int64, Float64}, key::Pair{Int64, Int64})
    @ Base .\dict.jl:498
  [2] macro expansion
    @ C:\Users\keijs\.julia\packages\JuMP\6RAQ9\src\macros\@variable.jl:277 [inlined]
  [3] (::var"#37#38"{Model})(i::Pair{Int64, Int64})
    @ Main C:\Users\keijs\.julia\packages\JuMP\6RAQ9\src\Containers\macro.jl:545
  [4] #87
    @ C:\Users\keijs\.julia\packages\JuMP\6RAQ9\src\Containers\container.jl:124 [inlined]
  [5] iterate
    @ .\generator.jl:47 [inlined]
  [6] collect(itr::Base.Generator{JuMP.Containers.VectorizedProductIterator{…}, JuMP.Containers.var"#87#89"{…}})
    @ Base .\array.jl:834
  [7] map(f::Function, A::JuMP.Containers.VectorizedProductIterator{Tuple{Dict{Int64, Int64}}})
    @ Base .\abstractarray.jl:3313
  [8] container(f::Function, indices::JuMP.Containers.VectorizedProductIterator{…}, ::Type{…}, names::Vector{…})
    @ JuMP.Containers C:\Users\keijs\.julia\packages\JuMP\6RAQ9\src\Containers\container.jl:123
  [9] container(f::Function, indices::JuMP.Containers.VectorizedProductIterator{…}, ::Type{…}, names::Vector{…})
    @ JuMP.Containers C:\Users\keijs\.julia\packages\JuMP\6RAQ9\src\Containers\container.jl:75
 [10] macro expansion
    @ C:\Users\keijs\.julia\packages\JuMP\6RAQ9\src\macros.jl:393 [inlined]
 [11] top-level scope
    @ c:\Users\keijs\Chalmers\Olinjär optimering\Project\model.jl:15
Some type information was truncated. Use `show(err)` to see complete types.

```

But should probably mark this as resolved as that was the main problem I was asking about, right?

---

<div class="post-metadata">

### Author: ![Jeff\_Emanuel](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jeff_emanuel/32/15440_2.png) [@Jeff\_Emanuel](https://discourse.julialang.org/u/Jeff_Emanuel)
#### Post date: [September 25, 2024, 7:11pm UTC](https://discourse.julialang.org/t/error-ioerror-symlink-operation-not-permitted-eperm/119872/4 "2024-09-25T19:11:02Z")

</div>

> [@Jesper\_Keijser](#):
>
> `P_G[i in generators] `

You probably want to iterate over either the keys or values of `generators`, not the pairs. You don’t have pairs as keys in `P_G`.

> [@Jesper\_Keijser](#):
>
> ```julia
> KeyError: key 5 => 4 not found
> Stacktrace:
> [1] getindex(h::Dict{Int64, Float64}, key::Pair{Int64, Int64})
> 
> ```

---

<div class="post-metadata">

### Author: ![Jesper\_Keijser](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jesper_keijser/32/212232_2.png) [@Jesper\_Keijser](https://discourse.julialang.org/u/Jesper_Keijser)
#### Post date: [September 26, 2024, 6:58am UTC](https://discourse.julialang.org/t/error-ioerror-symlink-operation-not-permitted-eperm/119872/5 "2024-09-26T06:58:23Z")

</div>

yes, this did resolve it. I iterated over keys(generators) instead. Thank you!