# ERROR: GitError(Code:ERROR, Class:Index, Invalid data in index - incorrect header signature)

**URL:** <https://discourse.julialang.org/t/error-giterror-code-error-class-index-invalid-data-in-index-incorrect-header-signature/12756>\
**Category:** General Usage\
**Tags:** question, package\
**Created:** [July 30, 2018, 10:47pm UTC](https://discourse.julialang.org/t/error-giterror-code-error-class-index-invalid-data-in-index-incorrect-header-signature/12756 "2018-07-30T22:47:22Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![Ian-B](https://avatars.discourse-cdn.com/v4/letter/i/71e660/32.png) [@Ian-B](https://discourse.julialang.org/u/Ian-B)\
**Post date:** [July 30, 2018, 10:47pm UTC](https://discourse.julialang.org/t/error-giterror-code-error-class-index-invalid-data-in-index-incorrect-header-signature/12756/1 "2018-07-30T22:47:22Z")

</div>

Hi! I’ve been trying to use Julia but I keep getting the same error when i try to install a package. I get this:

julia\> Pkg.update()  
INFO: Updating METADATA…  
ERROR: GitError(Code:ERROR, Class:Index, Invalid data in index - incorrect header signature)  
Stacktrace:  
[1] macro expansion at .\libgit2\error.jl:99 [inlined]  
[2] #diff\_tree#68(::Bool, ::Function, ::Base.LibGit2.GitRepo, ::Base.LibGit2.GitTree, ::String) at .\libgit2\diff.jl:22  
[3] (::Base.LibGit2.#kw##diff\_tree)(::Array{Any,1}, ::Base.LibGit2.#diff\_tree, ::Base.LibGit2.GitRepo, ::Base.LibGit2.GitTree, ::String) at .\<missing\>:0  
[4] #isdiff#76(::Bool, ::Function, ::Base.LibGit2.GitRepo, ::String, ::String) at .\libgit2\libgit2.jl:149  
[5] (::Base.LibGit2.#kw##isdiff)(::Array{Any,1}, ::Base.LibGit2.#isdiff, ::Base.LibGit2.GitRepo, ::String, ::String) at .\<missing\>:0  
[6] isfixed(::String, ::Base.LibGit2.GitRepo, ::Dict{VersionNumber,Base.Pkg.Types.Available}) at .\pkg\read.jl:64  
[7] #7 at .\pkg\read.jl:213 [inlined]  
[8] with(::Base.Pkg.Read.##7#8{Dict{String,Tuple{VersionNumber,Bool}}}, ::Base.LibGit2.GitRepo) at .\libgit2\types.jl:608  
[9] installed(::Dict{String,Dict{VersionNumber,Base.Pkg.Types.Available}}) at .\pkg\read.jl:211  
[10] update(::String, ::Set{String}) at .\pkg\entry.jl:393  
[11] (::Base.Pkg.Dir.##4#7{Array{Any,1},Base.Pkg.Entry.#update,Tuple{String,Set{String}}})() at .\pkg\dir.jl:36  
[12] cd(::Base.Pkg.Dir.##4#7{Array{Any,1},Base.Pkg.Entry.#update,Tuple{String,Set{String}}}, ::String) at .\file.jl:59  
[13] #cd#1(::Array{Any,1}, ::Function, ::Function, ::String, ::Vararg{Any,N} where N) at .\pkg\dir.jl:36  
[14] update() at .\pkg\pkg.jl:228

Does anybody know how to fix it? I would really appriciate it.Thanks