After I moved the project to the new version, a bunch of errors flew out, how to fix it?

Question

Unity

Moved the project to a newer version - a bunch of errors flew out. Rearranged another to an older version - it also crashes a bunch of errors. By errors, it is not very clear about the absence of what it complains about.

Answer 1

I had exactly the same problem. They suggested updating the editor to a new version.
I fiddled with this case for a couple of days, as a result, I demolished the unity hub, the editor and all the residual files. Rearranged on a new one, opened the project on a newer version of the editor and it worked (don't try the old version again. It won't work in any case, because it can only update files in one direction, it won't work back). Try to reinstall the unit too, because it is simply useless to deal with this number of errors.

Answer 2

You have an error in the libraries, most likely projects on new versions are not compatible with the old ones, or reinstall Unity.