# About Package installation

**URL:** <https://discourse.julialang.org/t/about-package-installation/20019>\
**Category:** New to Julia\
**Tags:** question, package\
**Created:** [January 24, 2019, 6:35am UTC](https://discourse.julialang.org/t/about-package-installation/20019 "2019-01-24T06:35:21Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![johnysy](https://avatars.discourse-cdn.com/v4/letter/j/8e7dd6/32.png) [@johnysy](https://discourse.julialang.org/u/johnysy)\
**Post date:** [January 24, 2019, 6:35am UTC](https://discourse.julialang.org/t/about-package-installation/20019/1 "2019-01-24T06:35:21Z")

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I am using NLOptControl for my simulation. Why can’t i install it through Pkg.add(), and I can install it by using Pkg.add(PackageSpec(url=“”)) but i still can’t use the package by typing using NLOptControl, it said that there’s extra token OCP and faiked to precompile

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**Author:** ![rdeits](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/rdeits/32/286_2.png) [@rdeits](https://discourse.julialang.org/u/rdeits)\
**Post date:** [January 24, 2019, 12:57pm UTC](https://discourse.julialang.org/t/about-package-installation/20019/2 "2019-01-24T12:57:57Z")

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Can you please post the actual code you ran and the full error message? Without at least that information there’s almost nothing we can do to help you.

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**Author:** ![fredrikekre](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/fredrikekre/32/1688_2.png) [@fredrikekre](https://discourse.julialang.org/u/fredrikekre)\
**Post date:** [January 24, 2019, 1:24pm UTC](https://discourse.julialang.org/t/about-package-installation/20019/3 "2019-01-24T13:24:10Z")

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```julia
(v1) pkg> add NLOptControl
 Resolving package versions...
ERROR: Unsatisfiable requirements detected for package NLOptControl [290757bd]:
 NLOptControl [290757bd] log:
 ├─possible versions are: 0.1.2-0.1.6 or uninstalled
 ├─restricted to versions * by an explicit requirement, leaving only versions 0.1.2-0.1.6
 └─restricted by julia compatibility requirements to versions: uninstalled — no versions left

```

The `restricted by julia compatibility requirements to versions: uninstalled — no versions left` part means that the package does not support Julia v1.

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**Author:** ![johnysy](https://avatars.discourse-cdn.com/v4/letter/j/8e7dd6/32.png) [@johnysy](https://discourse.julialang.org/u/johnysy)\
**Post date:** [January 24, 2019, 5:08pm UTC](https://discourse.julialang.org/t/about-package-installation/20019/4 "2019-01-24T17:08:45Z")

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I have tried to use julia 0.7.0. I can install the package now, but when I typed using NLOptControl  
LoadError: Failed to precompile NLOptControl [290757bd-39a7-5095-97bb-ca0f46959724] to C:\Users\微星.julia\compiled\v0.7\NLOptControl\Ua2jx.ji.

in expression starting at C:\Users\微星\Desktop\UM\_WINTER\julia\YSY\compiler.jl:1

macro expansion at logging.jl:313 [inlined]

compilecache(::Base.PkgId, ::String) at loading.jl:1185

macro expansion at logging.jl:311 [inlined]

\_require(::Base.PkgId) at loading.jl:941

require(::Base.PkgId) at loading.jl:852

macro expansion at logging.jl:311 [inlined]

require(::Module, ::Symbol) at loading.jl:834

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<div class="post-metadata">

**Author:** ![johnysy](https://avatars.discourse-cdn.com/v4/letter/j/8e7dd6/32.png) [@johnysy](https://discourse.julialang.org/u/johnysy)\
**Post date:** [January 24, 2019, 5:09pm UTC](https://discourse.julialang.org/t/about-package-installation/20019/5 "2019-01-24T17:09:05Z")

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Yes . That is the exact problem i am having! Is there any way to fix it ?

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**Author:** ![johnysy](https://avatars.discourse-cdn.com/v4/letter/j/8e7dd6/32.png) [@johnysy](https://discourse.julialang.org/u/johnysy)\
**Post date:** [January 24, 2019, 5:09pm UTC](https://discourse.julialang.org/t/about-package-installation/20019/6 "2019-01-24T17:09:08Z")

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So I might use julia0.7.0?

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**Author:** ![mbauman](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mbauman/32/31082_2.png) [@mbauman](https://discourse.julialang.org/u/mbauman)\
**Post date:** [January 24, 2019, 5:10pm UTC](https://discourse.julialang.org/t/about-package-installation/20019/7 "2019-01-24T17:10:34Z")

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Sorry @johnysy — I approved those posts in the wrong order. Now that you’ve posted more than twice you won’t hit the moderation queue anymore.