Resolved Collab package errors upon initiating a project from 2 years ago

I am trying to open a project from a couple of years ago (Unity version: 2020.3.19f1) which I have copied & sent over to a different PC (deleted obj & Library folders), and I get the following errors:


I remember using the collab feature to transfer data at the time from a different device, but I don't know what to do with these errors

 

I don't think Collab is even supported anymore. You might need to google around for an old supported version.

Or it could be extra unwanted packages in new projects (collab, testing, rider and other junk):

https://forum.unity.com/threads/temp-unityengine-testrunner-dll-error.1133938/#post-7287748

About the fastest way I have found to make a project and avoid all this noise is to create the project, then as soon as you see the files appear, FORCE-STOP (hard-kill) Unity (with the Activity Manager or Task Manager), then go hand-edit the Packages/manifest.json file as outlined in the above post, then reopen Unity.

Sometimes the package system gets borked from all this unnecessary churn and requires the package cache to be cleared:

https://stackoverflow.com/questions/53145919/unity3d-package-cache-errors/69779122

 

I removed everything from package cache & deleted collab package from manifest.json & it's all working now, thanks!