# Error installing RCall and Feather

**URL:** <https://discourse.julialang.org/t/error-installing-rcall-and-feather/32100>\
**Category:** New to Julia\
**Created:** [December 10, 2019, 2:27pm UTC](https://discourse.julialang.org/t/error-installing-rcall-and-feather/32100 "2019-12-10T14:27:38Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![curious](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/curious/32/7629_2.png) [@curious](https://discourse.julialang.org/u/curious)\
**Post date:** [December 10, 2019, 2:27pm UTC](https://discourse.julialang.org/t/error-installing-rcall-and-feather/32100/1 "2019-12-10T14:27:38Z")

</div>

I am getting the following error when trying to add the RCall package. Got the same error when I tried installing Feather before RCall. I don’t understand what is wrong. Would appreciate if someone can help.

Thank you.

**Stacktrace**

```julia
Pkg.add("RCall")
 Resolving package versions...
ERROR: MethodError: Cannot `convert` an object of type Nothing to an object of type String
Closest candidates are:
  convert(::Type{T<:AbstractString}, ::T<:AbstractString) where T<:AbstractString at strings/basic.jl:208
  convert(::Type{T<:AbstractString}, ::AbstractString) where T<:AbstractString at strings/basic.jl:209
  convert(::Type{T}, ::T) where T at essentials.jl:167
Stacktrace:
 [1] setindex!(::Dict{Base.UUID,String}, ::Nothing, ::Base.UUID) at /Applications/JuliaPro-1.2.0-1.app/Contents/Resources/julia/Contents/Resources/julia/lib/julia/sys.dylib:?
 [2] deps_graph(::Pkg.Types.Context, ::Dict{Base.UUID,String}, ::Dict{Base.UUID,Pkg.Types.VersionSpec}, ::Dict{Base.UUID,Pkg.Types.Fixed}) at /Applications/JuliaPro-1.2.0-1.app/Contents/Resources/julia/Contents/Resources/julia/lib/julia/sys.dylib:?
 [3] resolve_versions!(::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}, ::Nothing) at /Applications/JuliaPro-1.2.0-1.app/Contents/Resources/julia/Contents/Resources/julia/lib/julia/sys.dylib:?
 [4] #add_or_develop#63(::Array{Base.UUID,1}, ::Symbol, ::typeof(Pkg.Operations.add_or_develop), ::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}) at /Applications/JuliaPro-1.2.0-1.app/Contents/Resources/julia/Contents/Resources/julia/lib/julia/sys.dylib:?
 [5] #add_or_develop#17(::Symbol, ::Bool, ::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}, ::typeof(Pkg.API.add_or_develop), ::Pkg.Types.Context, ::Array{Pkg.Types.PackageSpec,1}) at /Applications/JuliaPro-1.2.0-1.app/Contents/Resources/julia/Contents/Resources/julia/lib/julia/sys.dylib:?
 [6] #add_or_develop#12(::Base.Iterators.Pairs{Symbol,Symbol,Tuple{Symbol},NamedTuple{(:mode,),Tuple{Symbol}}}, ::typeof(Pkg.API.add_or_develop), ::String) at /Applications/JuliaPro-1.2.0-1.app/Contents/Resources/julia/Contents/Resources/julia/lib/julia/sys.dylib:?
 [7] add(::String) at /Applications/JuliaPro-1.2.0-1.app/Contents/Resources/julia/Contents/Resources/julia/lib/julia/sys.dylib:?
 [8] top-level scope at REPL[3]:1

```

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<div class="post-metadata">

**Author:** ![dmbates](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/dmbates/32/44_2.png) [@dmbates](https://discourse.julialang.org/u/dmbates)\
**Post date:** [December 10, 2019, 10:00pm UTC](https://discourse.julialang.org/t/error-installing-rcall-and-feather/32100/2 "2019-12-10T22:00:33Z")

</div>

It appears that you are using `JuliaPro-1.2.0`. Have you tried with the standard Julia distribution from [Download Julia](https://julialang.org/downloads) ?

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<div class="post-metadata">

**Author:** ![curious](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/curious/32/7629_2.png) [@curious](https://discourse.julialang.org/u/curious)\
**Post date:** [December 11, 2019, 12:39am UTC](https://discourse.julialang.org/t/error-installing-rcall-and-feather/32100/3 "2019-12-11T00:39:34Z")

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Yes, it worked with the standard (stable) version 1.0.5. Thanks.