# Error: Error during loading of extension SymbolicsForwardDiffExt of Symbolics

**URL:** <https://discourse.julialang.org/t/error-error-during-loading-of-extension-symbolicsforwarddiffext-of-symbolics/118313>\
**Category:** General Usage\
**Tags:** question, package, symbolics\
**Created:** [August 17, 2024, 6:21pm UTC](https://discourse.julialang.org/t/error-error-during-loading-of-extension-symbolicsforwarddiffext-of-symbolics/118313 "2024-08-17T18:21:40Z")\
**Posts on this page:** 8\
**Page:** 1

<div class="post-metadata">

**Author:** ![ufechner7](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ufechner7/32/51363_2.png) [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Post date:** [August 17, 2024, 6:21pm UTC](https://discourse.julialang.org/t/error-error-during-loading-of-extension-symbolicsforwarddiffext-of-symbolics/118313/1 "2024-08-17T18:21:40Z")

</div>

I am getting the following error when installing my project [Tethers.jl](https://github.com/ufechner7/Tethers.jl):

```julia
  283 dependencies successfully precompiled in 295 seconds. 9 already precompiled.
  2 dependencies had output during precompilation:
┌ Symbolics → SymbolicsForwardDiffExt
│ ┌ Warning: Module SymbolicsForwardDiffExt with build ID ffffffff-ffff-ffff-0000-0048b61f8cdf is missing from the cache.
│ │ This may mean SymbolicsForwardDiffExt [4a213a23-c09c-5cde-9712-b631ad2c72df] does not support precompilation but is imported by a module that does.
│ └ @ Base loading.jl:1948
│ ┌ Error: Error during loading of extension SymbolicsForwardDiffExt of Symbolics, use `Base.retry_load_extensions()` to retry.
│ │ exception =
│ │ 1-element ExceptionStack:
│ │ Declaring __precompile__ (false) is not allowed in files that are being precompiled.
│ │ Stacktrace:
│ │ [1] _require(pkg::Base.PkgId, env::Nothing)
│ │ @ Base ./loading.jl:1952
│ │ [2] __require_prelocked(uuidkey::Base.PkgId, env::Nothing)
│ │ @ Base ./loading.jl:1812
│ │ [3] #invoke_in_world#3
│ │ @ ./essentials.jl:926 [inlined]
│ │ [4] invoke_in_world
│ │ @ ./essentials.jl:923 [inlined]
│ │ [5] _require_prelocked
│ │ @ ./loading.jl:1803 [inlined]
│ │ [6] _require_prelocked
│ │ @ ./loading.jl:1802 [inlined]
│ │ [7] run_extension_callbacks(extid::Base.ExtensionId)
│ │ @ Base ./loading.jl:1295
│ │ [8] run_extension_callbacks(pkgid::Base.PkgId)
│ │ @ Base ./loading.jl:1330
│ │ [9] run_package_callbacks(modkey::Base.PkgId)
│ │ @ Base ./loading.jl:1164
│ │ [10] __require_prelocked(uuidkey::Base.PkgId, env::String)
│ │ @ Base ./loading.jl:1819
│ │ [11] #invoke_in_world#3
│ │ @ ./essentials.jl:926 [inlined]
│ │ [12] invoke_in_world
│ │ @ ./essentials.jl:923 [inlined]
│ │ [13] _require_prelocked(uuidkey::Base.PkgId, env::String)
│ │ @ Base ./loading.jl:1803
│ │ [14] macro expansion
│ │ @ ./loading.jl:1790 [inlined]
│ │ [15] macro expansion
│ │ @ ./lock.jl:267 [inlined]
│ │ [16] __require(into::Module, mod::Symbol)
│ │ @ Base ./loading.jl:1753
│ │ [17] #invoke_in_world#3
│ │ @ ./essentials.jl:926 [inlined]
│ │ [18] invoke_in_world
│ │ @ ./essentials.jl:923 [inlined]
│ │ [19] require(into::Module, mod::Symbol)
│ │ @ Base ./loading.jl:1746
│ │ [20] include
│ │ @ ./Base.jl:495 [inlined]
│ │ [21] include_package_for_output(pkg::Base.PkgId, input::String, depot_path::Vector{String}, dl_load_path::Vector{String}, load_path::Vector{String}, concrete_deps::Vector{Pair{Base.PkgId, UInt128}}, source::String)
│ │ @ Base ./loading.jl:2222
│ │ [22] top-level scope
│ │ @ stdin:3
│ │ [23] eval
│ │ @ ./boot.jl:385 [inlined]
│ │ [24] include_string(mapexpr::typeof(identity), mod::Module, code::String, filename::String)
│ │ @ Base ./loading.jl:2076
│ │ [25] include_string
│ │ @ ./loading.jl:2086 [inlined]
│ │ [26] exec_options(opts::Base.JLOptions)
│ │ @ Base ./client.jl:316
│ │ [27] _start()
│ │ @ Base ./client.jl:552
│ └ @ Base loading.jl:1301
└  
┌ Symbolics → SymbolicsPreallocationToolsExt
│ ┌ Warning: Module SymbolicsPreallocationToolsExt with build ID ffffffff-ffff-ffff-0000-00466b16b60b is missing from the cache.
│ │ This may mean SymbolicsPreallocationToolsExt [d479e226-fb54-5ebe-a75e-a7af7f39127f] does not support precompilation but is imported by a module that does.
│ └ @ Base loading.jl:1948
│ ┌ Error: Error during loading of extension SymbolicsPreallocationToolsExt of Symbolics, use `Base.retry_load_extensions()` to retry.
│ │ exception =
│ │ 1-element ExceptionStack:
│ │ Declaring __precompile__ (false) is not allowed in files that are being precompiled.
│ │ Stacktrace:
│ │ [1] _require(pkg::Base.PkgId, env::Nothing)
│ │ @ Base ./loading.jl:1952
│ │ [2] __require_prelocked(uuidkey::Base.PkgId, env::Nothing)
│ │ @ Base ./loading.jl:1812
│ │ [3] #invoke_in_world#3
│ │ @ ./essentials.jl:926 [inlined]
│ │ [4] invoke_in_world
│ │ @ ./essentials.jl:923 [inlined]
│ │ [5] _require_prelocked
│ │ @ ./loading.jl:1803 [inlined]
│ │ [6] _require_prelocked
│ │ @ ./loading.jl:1802 [inlined]
│ │ [7] run_extension_callbacks(extid::Base.ExtensionId)
│ │ @ Base ./loading.jl:1295
│ │ [8] run_extension_callbacks(pkgid::Base.PkgId)
│ │ @ Base ./loading.jl:1330
│ │ [9] run_package_callbacks(modkey::Base.PkgId)
│ │ @ Base ./loading.jl:1164
│ │ [10] __require_prelocked(uuidkey::Base.PkgId, env::String)
│ │ @ Base ./loading.jl:1819
│ │ [11] #invoke_in_world#3
│ │ @ ./essentials.jl:926 [inlined]
│ │ [12] invoke_in_world
│ │ @ ./essentials.jl:923 [inlined]
│ │ [13] _require_prelocked(uuidkey::Base.PkgId, env::String)
│ │ @ Base ./loading.jl:1803
│ │ [14] macro expansion
│ │ @ ./loading.jl:1790 [inlined]
│ │ [15] macro expansion
│ │ @ ./lock.jl:267 [inlined]
│ │ [16] __require(into::Module, mod::Symbol)
│ │ @ Base ./loading.jl:1753
│ │ [17] #invoke_in_world#3
│ │ @ ./essentials.jl:926 [inlined]
│ │ [18] invoke_in_world
│ │ @ ./essentials.jl:923 [inlined]
│ │ [19] require(into::Module, mod::Symbol)
│ │ @ Base ./loading.jl:1746
│ │ [20] include
│ │ @ ./Base.jl:495 [inlined]
│ │ [21] include_package_for_output(pkg::Base.PkgId, input::String, depot_path::Vector{String}, dl_load_path::Vector{String}, load_path::Vector{String}, concrete_deps::Vector{Pair{Base.PkgId, UInt128}}, source::String)
│ │ @ Base ./loading.jl:2222
│ │ [22] top-level scope
│ │ @ stdin:3
│ │ [23] eval
│ │ @ ./boot.jl:385 [inlined]
│ │ [24] include_string(mapexpr::typeof(identity), mod::Module, code::String, filename::String)
│ │ @ Base ./loading.jl:2076
│ │ [25] include_string
│ │ @ ./loading.jl:2086 [inlined]
│ │ [26] exec_options(opts::Base.JLOptions)
│ │ @ Base ./client.jl:316
│ │ [27] _start()
│ │ @ Base ./client.jl:552
│ └ @ Base loading.jl:1301
└  

```

See: [relax requirements · ufechner7/Tethers.jl@7f2ece9 · GitHub](https://github.com/ufechner7/Tethers.jl/actions/runs/10434217661/job/28896858747) Julia 1.10 on Ubuntu, section julia-runtests

Why do I get error messages, and the tests pass?

This is very confusing for my users.

Shall I report a bug in `Symbolics.jl` ?

---

<div class="post-metadata">

**Author:** ![ChrisRackauckas](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chrisrackauckas/32/77_2.png) [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)\
**Post date:** [August 17, 2024, 7:54pm UTC](https://discourse.julialang.org/t/error-error-during-loading-of-extension-symbolicsforwarddiffext-of-symbolics/118313/2 "2024-08-17T19:54:00Z")

</div>

It’s been reported. It’s a bit fishy since it doesn’t report on all Julia versions. See the issues. I just put a patch this morning that should’ve fixed it, but if there’s still reports then maybe it did not.

---

<div class="post-metadata">

**Author:** ![ufechner7](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ufechner7/32/51363_2.png) [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Post date:** [August 17, 2024, 8:00pm UTC](https://discourse.julialang.org/t/error-error-during-loading-of-extension-symbolicsforwarddiffext-of-symbolics/118313/3 "2024-08-17T20:00:43Z")

</div>

But if you committed a patch this morning it cannot be in any released version yet. So I wait for the next release and test again.

---

<div class="post-metadata">

**Author:** ![ChrisRackauckas](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chrisrackauckas/32/77_2.png) [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)\
**Post date:** [August 17, 2024, 8:06pm UTC](https://discourse.julialang.org/t/error-error-during-loading-of-extension-symbolicsforwarddiffext-of-symbolics/118313/4 "2024-08-17T20:06:19Z")

</div>

It’s v6.2

---

<div class="post-metadata">

**Author:** ![ufechner7](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ufechner7/32/51363_2.png) [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Post date:** [August 17, 2024, 8:34pm UTC](https://discourse.julialang.org/t/error-error-during-loading-of-extension-symbolicsforwarddiffext-of-symbolics/118313/5 "2024-08-17T20:34:24Z")

</div>

Not fixed in Symbolics v6.2: [add Symbolics 6.2 · ufechner7/Tethers.jl@d548ded · GitHub](https://github.com/ufechner7/Tethers.jl/actions/runs/10434978999/job/28898455852)

```julia
(Tethers) pkg> st
Project Tethers v0.2.0
Status `~/repos/Tethers.jl/Project.toml`
  [8f4d0f93] Conda v1.10.2
  [992eb4ea] CondaPkg v0.2.23
  [23c2ee80] ControlPlots v0.1.5
  [16fef848] LiveServer v1.3.1
  [961ee093] ModelingToolkit v9.33.0
  [1dea7af3] OrdinaryDiffEq v6.87.0
  [9b87118b] PackageCompiler v2.1.17
  [d96e819e] Parameters v0.12.3
  [438e738f] PyCall v1.96.4
  [0c5d862f] Symbolics v6.2.0
  [21f18d07] Timers v0.1.5
  [37e2e46d] LinearAlgebra
  [44cfe95a] Pkg v1.10.0
  [8dfed614] Test

```

---

<div class="post-metadata">

**Author:** ![ChrisRackauckas](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chrisrackauckas/32/77_2.png) [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)\
**Post date:** [August 17, 2024, 10:31pm UTC](https://discourse.julialang.org/t/error-error-during-loading-of-extension-symbolicsforwarddiffext-of-symbolics/118313/6 "2024-08-17T22:31:43Z")

</div>

That’s not good.

---

<div class="post-metadata">

**Author:** ![ufechner7](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ufechner7/32/51363_2.png) [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Post date:** [August 18, 2024, 8:14am UTC](https://discourse.julialang.org/t/error-error-during-loading-of-extension-symbolicsforwarddiffext-of-symbolics/118313/7 "2024-08-18T08:14:22Z")

</div>

Can you share a link for an exiting issue where this issue has been reported? I cannot find it.

---

<div class="post-metadata">

**Author:** ![ufechner7](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ufechner7/32/51363_2.png) [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Post date:** [August 22, 2024, 6:54pm UTC](https://discourse.julialang.org/t/error-error-during-loading-of-extension-symbolicsforwarddiffext-of-symbolics/118313/8 "2024-08-22T18:54:53Z")

</div>

This seams to be fixed with this pull request of [make LabelledArrays an extension by KristofferC · Pull Request #637 · JuliaSymbolics/SymbolicUtils.jl · GitHub](https://github.com/JuliaSymbolics/SymbolicUtils.jl/pull/637) and the latest version of SymbolicUtils.

Thank you so much! 🙂