# DifferentialEquations loading error

**URL:** <https://discourse.julialang.org/t/differentialequations-loading-error/17054>\
**Category:** New to Julia\
**Created:** [November 1, 2018, 2:10pm UTC](https://discourse.julialang.org/t/differentialequations-loading-error/17054 "2018-11-01T14:10:10Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![HelgavonLichtenstein](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/helgavonlichtenstein/32/5005_2.png) [@HelgavonLichtenstein](https://discourse.julialang.org/u/HelgavonLichtenstein)\
**Post date:** [November 1, 2018, 2:10pm UTC](https://discourse.julialang.org/t/differentialequations-loading-error/17054/1 "2018-11-01T14:10:10Z")

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Hello,

I tried to run code from [Using DifferentialEquations.jl for a simple food-chain - #8 by ChrisRackauckas](https://discourse.julialang.org/t/using-differentialequations-jl-for-a-simple-food-chain/13576/8) but now I get an error:

```julia
julia> using DifferentialEquations
[Info: Recompiling stale cache file C:\Users\Helga\.julia\compiled\v1.0\DifferentialEquations\UQdwS.ji for DifferentialEquations [0c46a032-eb83-5123-abaf-570d42b7fbaa]
ERROR: LoadError: C:\Users\Helga\.julia\packages\SymEngine\sh7Yz\deps\symengine-0.3\bin\libmpc-3.dll cannot be opened, Please re-run Pkg.build("sh7Yz"), and restart Julia.

```

I am using Julia v 1.01 and DifferentialEquations has been previously installed and updated. I do not know how to re-run Pkg.build(“sh7Yz”).

Does anyone have advice on how to make DifferentialEquations run again?

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**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:** [November 1, 2018, 2:16pm UTC](https://discourse.julialang.org/t/differentialequations-loading-error/17054/2 "2018-11-01T14:16:50Z")

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That should be saying that you should run `]build SymEngine` or `]build DifferentialEquations`.

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<div class="post-metadata">

**Author:** ![HelgavonLichtenstein](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/helgavonlichtenstein/32/5005_2.png) [@HelgavonLichtenstein](https://discourse.julialang.org/u/HelgavonLichtenstein)\
**Post date:** [November 1, 2018, 2:26pm UTC](https://discourse.julialang.org/t/differentialequations-loading-error/17054/3 "2018-11-01T14:26:20Z")

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Such a quick response! Thank you!