The type "task" exist in both Unity.Tasks and mscorelib

Questions & Answers
1

I created a blank project with unity 2019.1.4f1. I imported the firebase SDK package for authentication and another google sign in package from here. I am basically trying to achieve google signin in android with firebase. But when I import the 2nd package ( google sign in), I get this error

Library\PackageCache\com.unity.textmeshpro@2.0.1\Scripts\Editor\TMP_PackageUtilities.cs(310,17): error CS0433: The type 'Task' exists in both 'Unity.Tasks, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' and 'mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'

I haven’t done anything else in the project, just imported. I have no idea what to do pls help

6

It actually states in the Firebase documentation (Adicionar o Firebase ao seu projeto do Unity  |  Firebase para Unity)

If you import a Firebase plugin that is incompatible with the .NET version enabled in your project, you’ll see compile errors from some types in the .NET framework that are implemented by the Parse SDK.

To resolve the compilation error, if you’re using .NET 3.x:

Remove or disable the following DLLs for all platforms:
Parse/Plugins/dotNet45/Unity.Compat.dll
Parse/Plugins/dotNet45/Unity.Tasks.dll
Enable the following DLLs for all platforms:
Parse/Plugins/Unity.Compat.dll
Parse/Plugins/Unity.Tasks.dll
To resolve the compilation error, if you’re using .NET 4.x:

Remove or disable the following DLLs for all platforms:
Parse/Plugins/Unity.Compat.dll
Parse/Plugins/Unity.Tasks.dll
Enable the following DLLs for all platforms:
Parse/Plugins/dotNet45/Unity.Compat.dll
Parse/Plugins/dotNet45/Unity.Tasks.dll

2

i dont really know why that happens since they are in different namespaces, but when you import the package you get a Unity.Task.dll, under plugins folder, try deleting it and use the system.thread task instead, if it doesnt work you will have to find how to remove the mscorelib (not sure if its posible)

4

I had this issue recently, and I found the solution was with a third party plugin called “Bolt”, if you are getting this error and have Bolt, update the build units and see if that works, if it doesn’t just reinstall Bolt and that worked for me.

For those getting this error and don’t have Bolt, my apologies that my solution doesn’t apply to you.

3

I’m getting the same problem. Is there a solution

5

See the answer here:

https://stackoverflow.com/questions/57401518/unity-migrating-to-2019-2-0f1-got-error-the-type-taskt-exists-in-both-unity