I think it is related to JetBrains Rider, but after upgrading to Unity 2020.2.6 (and also updated Rider yesterday), I got tons of errors in my Explorer window and the errors window bar. Although my project does not have any errors (and even in the script itself shows nothing, as you can see in the screenshot), the error seems to vanish only if I check file by file, one by one, which is a big problem (project is big).
I've tried already to clean up the cs project files, restarting project, etc. The errors does not go. And it was working good before the update. Any suggestions?
It does not really impact the project or any real errors. But having all those red marks and the Rider editor showing errors is very annoying.
EDIT: by pressing the "errors button", it goes file by file (opening) and then the error, for that file, disappears. But still, very odd and very annoying to go one by one.