An item with the same key has already been added.

After collaborate sync, following error and nothing appears at collab tab.

ArgumentException: An item with the same key has already been added. Key: Assets/Prefab/MonsterPrefab/Assassin/korean folder name/assassin.fbx.meta
System.Collections.Generic.Dictionary`2[TKey,TValue].TryInsert (TKey key, TValue value, System.Collections.Generic.InsertionBehavior behavior) (at <695d1cc93cca45069c528c15c9fdd749>:0)
System.Collections.Generic.Dictionary`2[TKey,TValue].Add (TKey key, TValue value) (at <695d1cc93cca45069c528c15c9fdd749>:0)
Unity.Cloud.Collaborate.Models.ChangesModel.UpdateChangeList (System.Collections.Generic.IReadOnlyList`1[T] list) (at Library/PackageCache/com.unity.collab-proxy@1.3.9/Editor/Models/ChangesModel.cs:175)
Unity.Cloud.Collaborate.Models.ChangesModel.OnReceivedChangeList (System.Collections.Generic.IReadOnlyList`1[T] list) (at Library/PackageCache/com.unity.collab-proxy@1.3.9/Editor/Models/ChangesModel.cs:140)
Unity.Cloud.Collaborate.Models.Providers.Collab.RequestChangeList (System.Action`1[T] callback) (at Library/PackageCache/com.unity.collab-proxy@1.3.9/Editor/Models/Providers/Collab.cs:462)
Unity.Cloud.Collaborate.Models.ChangesModel.RequestInitialData () (at Library/PackageCache/com.unity.collab-proxy@1.3.9/Editor/Models/ChangesModel.cs:347)
Unity.Cloud.Collaborate.Presenters.ChangesPresenter.PopulateInitialData () (at Library/PackageCache/com.unity.collab-proxy@1.3.9/Editor/Presenters/ChangesPresenter.cs:80)
Unity.Cloud.Collaborate.Presenters.ChangesPresenter.Start () (at Library/PackageCache/com.unity.collab-proxy@1.3.9/Editor/Presenters/ChangesPresenter.cs:47)
Unity.Cloud.Collaborate.Views.ChangesTabPageView.SetActive () (at Library/PackageCache/com.unity.collab-proxy@1.3.9/Editor/Views/ChangesTabPageView.cs:113)
Unity.Cloud.Collaborate.Components.TabPageComponent.SetActive (System.Boolean active) (at Library/PackageCache/com.unity.collab-proxy@1.3.9/Editor/Components/TabPageComponent.cs:21)
Unity.Cloud.Collaborate.Components.TabView.SetActive () (at Library/PackageCache/com.unity.collab-proxy@1.3.9/Editor/Components/TabView.cs:57)
Unity.Cloud.Collaborate.Views.MainPageView.SetActive () (at Library/PackageCache/com.unity.collab-proxy@1.3.9/Editor/Views/MainPageView.cs:87)
Unity.Cloud.Collaborate.Components.PageComponent.SetActive (System.Boolean active) (at Library/PackageCache/com.unity.collab-proxy@1.3.9/Editor/Components/PageComponent.cs:21)
Unity.Cloud.Collaborate.UserInterface.CollaborateWindow.UpdateDisplayMode (Unity.Cloud.Collaborate.UserInterface.CollaborateWindow+Display newDisplay) (at Library/PackageCache/com.unity.collab-proxy@1.3.9/Editor/UserInterface/CollaborateWindow.cs:236)
Unity.Cloud.Collaborate.UserInterface.CollaborateWindow.OnUpdatedProjectStatus (Unity.Cloud.Collaborate.Models.Enums.ProjectStatus status) (at Library/PackageCache/com.unity.collab-proxy@1.3.9/Editor/UserInterface/CollaborateWindow.cs:178)
Unity.Cloud.Collaborate.UserInterface.CollaborateWindow.OnEnable () (at Library/PackageCache/com.unity.collab-proxy@1.3.9/Editor/UserInterface/CollaborateWindow.cs:127)

 

Fixed it by unlinking and linking project back. Not a real solution, but a workaround. At least it's working now
https://docs.unity3d.com/Manual/UnityCollaborateTroubleShooting.html

 

I had the exact same problem and unlinking and linking the project back does not solve it.

 

This error appeared for me again around 10 times, before I just said "f*ck it" and unlinked my project at all. Now I'm just using github for version controls. Yeah, you'll need to spend full day setting up the git, then change your workflow a bit, but now it's pretty smooth.
If you'll decide to do this too - don't use this asset, just connect the project by yourself

Pros: no more wierd not fixable errors
Cons: you can't see what's changed right in the inspector, also can't see who's working on what. But there are not a big deal
Note: make sure to commit .meta files along with everything. Without them project is unsuable, if you'll decide to clone it to other machine

 

don't use other characters ever other than English for file names.

 

Makes sense. I had problems only with files, which name was written on Russian.
Anyway, I'm already using github flawlessly