Temp/UnityEngine.TestRunner.dll Error

I am getting this error called failed to copy temp/UnityEngine.TestRunner.dll to some random folder that i cant remember. Unity just does not respond. I close the un responding window through task manager and restarted it and lost all of my work. I would say unity is dumb and annoying because of this. My project took me 2 hours to make and it is all gone. HELP!

 

Recent versions of unity have an annoying habit of crapping useless packages into your project. When those packages inevitably have errors, this sort of thing happens. I have railed about it before.

Go into the package manager and remove crap you don't need, like the entire test runner and collab and whatnot.

If you feel brave you can hand-edit the

Packages/manifest.json

file a lot faster than using the laggy package manager interface that only lets you remove one package at a time:

I'm sorry you've had this issue. Please consider using source control in order to guard and protect your hard-earned work.

Personally I use git because it is free and there are tons of tutorials out there to help you set it up.

As far as configuring Unity to play nice with git, keep this in mind:

https://forum.unity.com/threads/prefab-links-keep-getting-dumped-on-git-pull.646600/#post-7142306

Here's how I use git in one of my games, Jetpack Kurt:

https://forum.unity.com/threads/2-steps-backwards.965048/#post-6282497

Using fine-grained source control as you work to refine your engineering:

https://forum.unity.com/threads/whe...grammer-example-in-text.1048739/#post-6783740

Share/Sharing source code between projects:

https://forum.unity.com/threads/your-techniques-to-share-code-between-projects.575959/#post-3835837

Setting up the right .gitignore file:

https://forum.unity.com/threads/removing-il2cpp_cache-from-project.1084607/#post-6997067

Generally setting Unity up (includes above .gitignore concepts):

https://thoughtbot.com/blog/how-to-git-with-unity

 

Thanks for the help.
I am using the Unity version 2020.3.12f1.
Will I be able to make it work if I built my project in Unity version 2019.4.17f1 and then opened it in Unity 2020.3.12f1?

 

Upgrades are one-way UP to higher version numbers only.

ALWAYS use source control properly and TEST that you have used it properly before upgrading.

Personally I use git because it is free and there are tons of tutorials out there to help you set it up.

As far as configuring Unity to play nice with git, keep this in mind:

https://forum.unity.com/threads/prefab-links-keep-getting-dumped-on-git-pull.646600/#post-7142306

Here's how I use git in one of my games, Jetpack Kurt:

https://forum.unity.com/threads/2-steps-backwards.965048/#post-6282497

Using fine-grained source control as you work to refine your engineering:

https://forum.unity.com/threads/whe...grammer-example-in-text.1048739/#post-6783740

Share/Sharing source code between projects:

https://forum.unity.com/threads/your-techniques-to-share-code-between-projects.575959/#post-3835837

Setting up the right .gitignore file:

https://forum.unity.com/threads/removing-il2cpp_cache-from-project.1084607/#post-6997067

Generally setting Unity up (includes above .gitignore concepts):

https://thoughtbot.com/blog/how-to-git-with-unity

 

I don't know how to set up source control or git and i am not wasting my time on it

 

I got the same error, I accidently linked an old project ID to my current project, that had the old colloborate version still on it instead of the Plastic SCM. So, I just created a new product ID and linked it to my new project and the error went away.

 

Every time this error occurs, I'm tired of correcting it by referring to this site...

 

If you get this error, restart Unity. It should allow you to start unity in SafeMode. Once it comes up read the errors it gives you, most probably a file pointing to some plugin. It should state clearly where the file(s) are, delete them and Unity will restart by itself and your work is restored.