# Problems installing Agents under v1.12.0

**URL:** <https://discourse.julialang.org/t/problems-installing-agents-under-v1-12-0/133215>\
**Category:** Modelling & Simulations\
**Tags:** question, package, jld2, agents\
**Created:** [October 16, 2025, 8:05pm UTC](https://discourse.julialang.org/t/problems-installing-agents-under-v1-12-0/133215 "2025-10-16T20:05:00Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Niall](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/niall/32/22517_2.png) [@Niall](https://discourse.julialang.org/u/Niall)\
**Post date:** [October 16, 2025, 8:05pm UTC](https://discourse.julialang.org/t/problems-installing-agents-under-v1-12-0/133215/1 "2025-10-16T20:05:00Z")

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Hi. I’ve just returned to julia after absence and have installed version 1.12.0. I now have problems installing and loading a set of 8 packages relating to Agents. Here is the Pkg output:

```julia-auto
(@v1.12) pkg> up Agents
    Updating registry at `C:\Users\Niall\.julia\registries\General.toml`
     Project No packages added to or removed from `C:\Users\Niall\.julia\environments\v1.12\Project.toml`
    Manifest No packages added to or removed from `C:\Users\Niall\.julia\environments\v1.12\Manifest.toml`
  ✗ JLD2
  ✗ DynamicalSystems → DynamicalSystemsVisualizations
  ✗ MetaGraphs
  ✗ StaticGraphs
  ✗ LightOSM
  ✗ Agents
  ✗ Agents → AgentsVisualizations
Precompiling packages finished.
  0 dependencies successfully precompiled in 164 seconds. 553 already precompiled.
  7 dependencies errored.
  For a report of the errors see `julia> err`. To retry use `pkg> precompile`

```

The errors appear to stem from a problem with JLD2:

```julia-auto
ConcurrencyViolationError("deadlock detected in loading JLD2 using JLD2")

```

Is this something that is known about?

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<div class="post-metadata">

**Author:** ![Datseris](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/datseris/32/13406_2.png) [@Datseris](https://discourse.julialang.org/u/Datseris)\
**Post date:** [October 16, 2025, 8:23pm UTC](https://discourse.julialang.org/t/problems-installing-agents-under-v1-12-0/133215/2 "2025-10-16T20:23:28Z")

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Hi, for now please stick to Julia v1.11 if you’d like to use Agents.jl. You can follow this issue for updates on the topic: [`Agents.jl` does not precompile with Julia 1.12.0 (Linux) · Issue #1182 · JuliaDynamics/Agents.jl · GitHub](https://github.com/JuliaDynamics/Agents.jl/issues/1182)

(I also see that you are using `DynamicalSystems` that _also_ has not been updated to Julia v1.12. Oh how I wish minor, non-breaking releases of the language did not in fact break installing or using packages)

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**Author:** ![JonasIsensee](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jonasisensee/32/4704_2.png) [@JonasIsensee](https://discourse.julialang.org/u/JonasIsensee)\
**Post date:** [October 16, 2025, 8:41pm UTC](https://discourse.julialang.org/t/problems-installing-agents-under-v1-12-0/133215/3 "2025-10-16T20:41:11Z")

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Can you please check and that you are on the latest JLD2 release? ( \> 0.6 )

This looks like an issue that was fixed quite some time ago already.

Issue was: JLD2 precompile workload tried to precompile the FileIO.save API which tried to dynamically load JLD2…

* * *

**Actually**  
The problem is this:  
On julia 1.12 in a temp environment installing Agents gives an ancient JLD2 version that is not compatible with julia v1.12.

The problem is Agents → LightOSM → MetaGraphs (compat v0.7 but latest is v0.8) → JLD2 (old compat bound, latest MetaGraphs is compatible with latest JLD2)

Solution → get LightOSM to bump their compat bounds on MetaGraphs

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<div class="post-metadata">

**Author:** ![Datseris](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/datseris/32/13406_2.png) [@Datseris](https://discourse.julialang.org/u/Datseris)\
**Post date:** [October 16, 2025, 8:49pm UTC](https://discourse.julialang.org/t/problems-installing-agents-under-v1-12-0/133215/4 "2025-10-16T20:49:57Z")

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Thanks Jonas, someone already got us to it: [precompile fails on Julia v1.12.0 · Issue #111 · DeloitteOptimalReality/LightOSM.jl · GitHub](https://github.com/DeloitteOptimalReality/LightOSM.jl/issues/111)

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**Author:** ![Niall](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/niall/32/22517_2.png) [@Niall](https://discourse.julialang.org/u/Niall)\
**Post date:** [October 17, 2025, 4:42am UTC](https://discourse.julialang.org/t/problems-installing-agents-under-v1-12-0/133215/5 "2025-10-17T04:42:06Z")

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Thanks both of you.